"Science, Faculty of"@en . "Physics and Astronomy, Department of"@en . "DSpace"@en . "UBCV"@en . "Bedford, Ronald Ernest."@en . "2012-01-30T16:55:43Z"@en . "1955"@en . "Doctor of Philosophy - PhD"@en . "University of British Columbia"@en . "The spectra of arsenic have been photographed from the infra-red to the vacuum ultraviolet with a 21 foot grating, a 2 metre vacuum grating, a Littrow prism spectrograph, and a constant deviation spectrograph using an elect-rodeless discharge source. The wave lengths of 1500 lines in the region 550 to 9300 A have been measured relative to Iron standards. Some 300 of these were previously classified, chiefly in As I and As II. Another 500 have now been assigned to the various spark spectra, leaving less than 10% of the observed intensity unaccounted for. The chief extension has been made in As II with more than 50 new energy levels being established.\r\nThe resulting analyses have been critically examined in terms of the intermediate coupling relations proposed by M.H. Johnson* and the atomic energy relations due to Bacher and Goudsmit+. These relations permit the evaluation of important radial integrals of Slater, and the study for the first time of how these integrals changes both in the various spark spectra of an element and with the successive series members within a given spectrum For unperturbed configurations these theories are found to be satisfactory.\r\n*M.H. Johnson, Jr. Phys. Rev. 38, l628, 1931; 39, 197, 1932\r\n+ R.F. Bacher and S.A. Goudsmit, Phys. Rev. 46 948; 1934"@en . "https://circle.library.ubc.ca/rest/handle/2429/40360?expand=metadata"@en . "A S T U D Y OF T H E S P A R K S P E C T R A OF A R S E N I C by RONALD ERNEST BEDFORD . A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n PHYSICS We accept this thesis as conforming to the standard required from candidates for the degree of DOCTOR OF PHILOSOPHY. Members of the Department of Physics T H E U N I V E R S I T Y O F B R I T I S H C O L U M B I A September, 1955 THE UNIVERSITY OF BRITISH COLUMBIA F a c u l t y of Graduate Studies PROGRAMME OF THE FINAL ORAL EXAMINATION FOR THE DEGREE OF DOCTOR OF PHILOSOPHY RONALD ERNEST BEDFORD B\u00E2\u0080\u009ESc 8 (Manitoba) 19^2 M.A, ( B r i t i s h Columbia) 19^3 TUESDAY, August 30th, 1955 at 3:00 p em e i n ROOM 217, PHYSICS BUILDING COMMITTEE IN CHARGE W.H. Gage, Chairman of A 8M\u00E2\u0080\u009E Crooker G.M.. Shrum C.A. Barnes J 8 B . Brown C 0 Reid T.E. H u l l JaH, Creighton B.A. D u n e l l . E x t e r n a l Examiner: A.,E. Douglas, N a t i o n a l Research C o u n c i l , LIST OP PUBLICATIONS The Spectra of A r s e n i c : R 0E B Bedford and AolYL Crooker, P h y s i c a l Review 96, 8^5 (A), 195^3 ~~ The Hyp'erfine Structure of Mercury E x t r a c t e d from Neutron-Irradiated Gold; R eE 0 Bedford and A 0M 0 Crooker, Can\u00E2\u0080\u009E Journ 3 P h y s 3 J 33.? 25, 1955 3 THESIS A STUDY OF THE SPARK SPECTRA OF ARSENIC The spectra of ar s e n i c have been photo-graphed from the i n f r a - r e d to the vacuum u l t r a -v i o l e t with.a 21 foot g r a t i n g , a 2 metre vacuum g r a t i n g , a L I t t r o w prism spectrograph^ and a constant d e v i a t i o n spectrograph using an e l e c t -rodeless discharge source. The wave lengths of 1500 l i n e s i n the r e g i o n 5^0 to 9300 A have been measured r e l a t i v e to Iron standards 9 Some 300 of these were p r e v i o u s l y c l a s s i f i e d , , c h i e f -l y i n As I and As I I a Another 5>00 have now been assigned to the various spark s p e c t r a , l e a v i n g l e s s than 10% of the observed i n t e n s i t y unaccounted f o r e The c h i e f extension has been made i n As I I w i t h more than \u00C2\u00A30 new energy l e v e l s being e s t a b l i s h e d s The r e s u l t i n g analyses have been c r i t i c a l l y examined i n terms of the intermediate c o u p l i n g r e l a t i o n s proposed by M 3H 8 Johnson-::- and the atomic energy r e l a t i o n s due to Bacher and Goudsmit-fa These r e l a t i o n s permit the evalua-t i o n of important r a d i a l i n t e g r a l s of Slater,, and the study f o r the f i r s t time of how these i n t e g r a l s change s both i n the various spark spectra of an element and w i t h the successive s e r i e s members w i t h i n a given spectrum For unperturbed c o n f i g u r a t i o n s these t h e o r i e s are found to be s a t i s f a c t o r y . M 0H 0 Johnson, J r G Phys. Rev 0 ji8, l 6 2 8 s 1931; 39, 197, 1932 + R aF 9 Bacher and SeA\u00E2\u0080\u009E Goudsmit, Phys\u00C2\u00AB, Rev 0 lj.6 9i|-8; 193^ GRADUATE STUDIES F i e l d of Study: Physics Electromagnetic Theory Theory of Measurements E l e c t r o n i c s Quantum Mechanics Nuclear Physics Geophys i c s Spectroscopy Advanced Spectroscopy X-rays and C r y s t a l Structure S p e c i a l R e l a t i v i t y Quantum Theory of Ra d i a t i o n Molecular Spectroscopy W. Opechowski A.M. Crooker H.E.D. S c o v i l G.M. V o l k o f f K.C. Mann A.R. C l a r k 0. Theimer C. Gumming and A.M. Crooker J.B, Warren \u00C2\u00A5. Opechowski P.A. Kaempffer 0. Theimer Other Studies: I n t e g r a l Equations T eE. H u l l F o u r i e r Series and I n t e g r a l s F.M0C. Goodspeed Topics i n A p p l i e d Mathematics B.N. Moyls and T<,E. H u l l Theory of the Chemical Bond C. Reid UNIVERSITY OF SOTTISH COLUWBffiA OCT 3 1955 T H E L I B R A R Y ( i i ) TABLE OF CONTENTS Abstract Acknowledgements Chapter; I Introduction II Theory 1. General Theory of Atomic Spectra (a) n* Sequences (b) Moseley Diagrams (c) Irregular Doublet Law (d) Regular Doublet Law (e) Lande Interval Rule (f) Selection Rules (g) Intensity Sum Rule (h) Zeeman Effect 2. Theory of Complex Spectra (a) L - S Coupling (b) j - j Coupling ( c) 5 ~ \u00C2\u00A3 Coupling (d) Intermediate Coupling (e) Interconfiguration Perturbations (f) Theory of Limits 5i Atomic Energy Relations Page (vi) ( v i i ) 1 6 6 6 8 9 10 11 12 15 14 15 20 22 25 24 50 51 51 Table of Contents (continued) III Experimental 57 IV Results and Analysis 40 1. Arsenic I 42 2. Arsenic II 42 (a) Ionization Potential 4 j (b) Application of Intermediate and j - i Coupling 44 (c) Calculation of Slater Parameters i n Isoelectronic Spectra 49 (d) Theory of Limits 50 (e) Atomic Energy Relations 51 (f) Additional Remarks 52 5. Arsenic III 52 (a) Atomic Energy Relations 54 4. Arsenic IV . 55 5 . Arsenic V 56 V Resume 58 Bibliography 115 (iv) Table of Contents (continued) Tables: I Lande g Factors in (j -J[) Coupling 2 5 II Configuration s s' 5 ^ III Configuration p p' 54 IV Configuration s p s' 55 V Configuration s p p' 5 5 VI Results for s p s' and s p p' $6 VII L i s t of Classified Lines in As I 61 VIII Li s t of Classified Lines in As II 6 5 IX Terms of the As II Spectrum 78 X Configuration 4p 5p 4 5 XI g-factors for 4 p 5 s and 4 p 6 s 47 XII Slater Parameters in As II Isoflectronic Sequences 50 XIII Term Limits for 4p nj 51 XIV Lis t of Classified Lines in As III 8\u00C2\u00A3 XV Terms of the As III Spectrum \u00E2\u0080\u00A2 86* XVI Test of Atomic Energy Relations 5 5 XVII Lis t of Classified Lines i n As IV , 85! XVIII Terms of the As IV Spectrum 9\u00C2\u00A9 XIX L i s t of Classified Lines in As V 92 XX Terms of the As V Spectrum 9 $ XXI Lis t of Unclassified Arsenic Lines 9# XXII Slater Parameters from Arsenic Configurations 5 9 (v) Table of Contents (continued) Illustrations: 1. Rowland Ghost Separations for the 21 foot grating following page 4o 2. Moseley Diagram for As II Sequence 0 5. Moseley Diagram for As III Sequence 4. Moseley Diagram for As V Sequence following page 44 following page 54 following page 57 Plates: I E - 1 photograph of the arsenic spectrum with exposures of low, high and medium excitation respectively. Characteristic lines of each excitation are identified. 118 II E - 1 photograph of the arsenic spectrum with exposures of high and medium excitation respectively. Characteristic lines of each excitation are identified. 119 (vi) \u00E2\u0080\u00A2 . ABSTRACT The spectra of arsenic have been photographed from the infra-red to the vacuum ultra-violet with a 21 foot grating, a 2 metre vacuum grating, a Littrow prism spectrograph, and a constant deviation spectro-graph, using an electrodeless discharge source. The wavelengths of 1500 lines have been measured relative to iron standards i n the region 550 to 9500 angstroms. Some 5Q0 of these were previously classified, chiefly i n As I and As II. Another 500 have now been assigned to the various spark spectra, leaving leBS than 10$ of the observed intensity unaccounted for. The chief extension has been made in As-II with more than 60 new energy level-s being established. The resulting analyses have been c r i t i c a l l y examined in terms of intermediate coupling and the Bacher - Goudsmit atomic energy relations. When perturbations are not present these theories are found to be satisfactory. ( v i i ) ACKNOWLEDGEMENTS I wish to express my gratitude to Dr. A. M. Crooker for his supervision of this research. His unstinting cooperation and stimul-ating discussions have been a source of inspiration. It is a pleasure to acknowledge the technical assistance of Mr. J. Lees, Mr. E. Price, and Mr. A. Fraser. I am indebted to the National Research Council of Canada for the awards of a Studentship and Fellowship. 1 CHAPTER I INTRODUCTION During the period from roughly 1925 to 1955 there occurred unparalleled activity i n the investigation and analysis of atomic spectra. With the advent of quantum mechanics in 1927 the theory of spectra was given a very firm foundation. The semi-classical rules of the old quantum and Bohr theories became a natural consequence of the new quantum mechanics. As.developed by Slater, Goudsmit and B&cher, Condon and Shortley, and others, the theory was capable of explaining in a semi-quantitative way the major details of most spectra. Subsequent-ly interest i n the subject declined rapidly, particularly from the ex-perimental point of view. A f a i r l y widespread opinion arose that l i t t l e more of value could be gleaned from further study. That this opinion i s erroneous has been pointed out by many authors. A glance at the tables prepared by Shenstone (56) and Meggers (18), or at the \"Atomic Energy Levels\" compiled by Mrs. Moore-Sitterly (21), reveals the gaps which occur i n our knowledge of many spectra. Some are so incomplete as to be almost unknown. Indeed only 55 \"A's\" appear in Shenstone's table, while the number has been increased to about 100 by Meggers. The latter points out that we have information regarding only 12 percent of the theoretically possible spectra. Harrison (7) estimated that approx-imately one million lines must be ascribed to their parent ions i n order to meet the needs of astronomers, physicists, and chemists, whereas at that time only about 280,000 were known. If the theory of complex spectra i n terms of intermediate coupling parameters, Slater coefficients, interconfiguration perturbations, etc. is to be comprehensively tested a large number of f a i r l y complete analyses must be available. 2 The problems facing the present day spectroscopist are then as follows. In the f i r s t place the accuracy of existing wavelengths must be improved. The flurry of activity three decades ago resulted i n large numbers of lines measured on instruments with relatively low dispersion and resolving power. As w i l l be seen later i n the case of arsenic, the wavelengths which then found their way into literature may be exceedingly i n error. Modern equipment allows this deficiency to be corrected. Secondly, the regions of the spectrum explored must be ex-tended. Most of the early data included lines i n only the visible and near ultra-violet and this naturally represents a severe obstacle i n the subsequent determination of the energy levels. One can now observe photographically with comparative ease from the near infra-red to the vacuum ultra-violet. Standard wavelengths are now available through most of this region. The early analyses, many of which were only superficial and often incorrect, must be reexamined i n the light of new data and considerable extension carried out. Finally, this experimental data may be used to make a quantitative test of modern atomic theory, the most elegant form of which is probably that of Racah and his coworkers. The task is not an easy one. In the words of Shenstone (56): \"to complete an already pa r t i a l l y analysed spectrum i s much more d i f f i c u l t than to begin a new one because i t is always the easy part that is already done.\" The quantum theory of complex spectra was f i r s t developed by Slater (58) (see Chapter II, Section 2) who considered only the electro-static interaction between electrons i n a central force f i e l d . By applying standard perturbation theory he arrived at expressions for the energy levels involving certain integrals of the radial parts of one e l e c t r o n wave f u n c t i o n s . These S l a t e r i n t e g r a l s F , G may not be evaluated d i r e c t l y without assuming some p a r t i c u l a r form f o r the wave f u n c t i o n s and hence the p o t e n t i a l energy. They are commonly t r e a t e d as parameters t o be evaluated so as to give the best f i t w i t h experimental data. In the same year Houston (10) obtained by a c o r r e c t quantum mechanical procedure the energy l e v e l s f o r a two e l e c t r o n system con-s i s t i n g of one s and one a r b i t r a r y e l e c t r o n i n a s t a t e of a r b i t r a r y c o u p l i n g . Thus the magnetic i n t e r a c t i o n between the e l e c t r o n s was a l s o considered. The method was extended by Goudsmit (5) and Johnson (12) t o more general c o n f i g u r a t i o n s . These intermediate c o u p l i n g formulae i n v o l v e the magnetic i n t e r a c t i o n constants a^ of the v a r i o u s e l e c t r o n s as w e l l as the S l a t e r i n t e g r a l s . The numerical e v a l u a t i o n of the l e v e l s to o b t a i n a comparison w i t h experimental data i s a tedious a r i t h m e t i c a l procedure, and a survey of the l i t e r a t u r e shows t h a t such a t a s k has been attempted i n f a r too few cases. I n any p a r t i c u l a r spectrum c l o s e estimates of the constants a^ can u s u a l l y be made from * A a v a i l a b l e data, but t h i s i s not t r u e f o r F , G u n t i l n e a r l y a l l l e v e l s of a given c o n f i g u r a t i o n are l o c a t e d e x p e r i m e n t a l l y . Hence one may not \" p r e d i c t \" l e v e l s . I f from values of the parameters f o r a known c o n f i g -u r a t i o n one could estimate f a i r l y a c c u r a t e l y t h e i r values f o r other con-f i g u r a t i o n s then the intermediate c o u p l i n g formulae would become an extremely u s e f u l a n a l y t i c a l t o o l . One would p a r t i c u l a r l y l i k e to know t h e i r behaviour i n (a) a s e r i e s such as n l n ' l ' (n' = n, n * l , n*-2, . . . ) , and (b) the same c o n f i g u r a t i o n s of i s o e l e c t r o n i c s p e c t r a . Another approach to the c a l c u l a t i o n of atomic energy l e v e l s has been made by Bacher and Goudsmit (2) who developed r u l e s f o r e s t i m a t i n g 4 the absolute energies of an i o n i n terms of succeeding stages of i o n -i z a t i o n . They a p p l i e d the r e s u l t s t o carbon, n i t r o g e n , and oxygen and obtained good agreement w i t h experiment. Few a p p l i c a t i o n s of t h i s method appear to have been made, whereas they would seem t o represent a very powerful a i d i n the a n a l y s i s of spe c t r a . The f o l l o w i n g chapters w i l l describe the a p p l i c a t i o n of the fore g o i n g d i s c u s s i o n t o the spectra of a r s e n i c . To summarize, the pro-gramme g e n e r a l l y has been (a) t o determine as a c c u r a t e l y and completely as p o s s i b l e wavelengths from the i n f r a - r e d to the vacuum u l t r a - v i o l e t , (b) to attempt an extensive a n a l y s i s of the spark spectra u s i n g these improved measurements, and (c) to examine these analyses i n terms of intermediate c o u p l i n g . Among the e a r l i e s t measurements of the a r s e n i c s p e c t r a were those of Herpertz (15) Bloch and Bloch (3) , Queney (26), and R a n d a l l (28). None of these workers made any serious attempt a t c l a s s i f y i n g the l i n e s . Randall measured t e n i n f r a - r e d As I l i n e s w i t h the use of a thermocouple, while Queney's work was confined to the vacuum u l t r a - v i o l e t and c o n s i s t e d i n la r g e p a r t of h i g h e x c i t a t i o n l i n e s . The f i r s t attempts a t a n a l y z i n g the arc spectrum were made independently by K. R. Rao (52) and Meggers and de B r u i n (19) i n 1929, but the two i n t e r p r e t a t i o n s d i f f e r e d i n many i n s t a n c e s . Recently a thorough a n a l y s i s has been c a r r i e d out by Meggers, Shenstone, and Moore (20) who succeeded i n c l a s s i f y i n g 91% of the t o t a l i n t e n s i t y o f the observed l i n e s . The s i n g l y i o n i z e d a r s e n i c atom has as i t s ground s t a t e a 4 s a 4p* c o n f i g u r a t i o n and hence gives r i s e t o an exceedingly complex spectrum. I n 1922 A. 3. Rao (29) c l a s s i f i e d about 150 l i n e s as combinations between 22 terms and 14 miscellaneous l e v e l s . G a r t l e i n (21) i n 1950 confirmed 15 of these terms and 4 of the miscellaneous l e v e l s and remarked t h a t the spectrum s e r i o u s l y needed f u r t h e r i n v e s t i g a t i o n . As I I I was f i r s t s tudied by Pattabhiramiah and Rao (24), and by Rao and Narayan (20), but i t was l a t e r shown th a t most of the l i n e s there as-c r i b e d to As I I I a c t u a l l y arose from As I I . The most important c o n t r i b -u t i o n s have been made by Lang (16) and K. R. Rao (22) who designated 6 odd and 12 even l e v e l s as accounting f o r about 4o l i n e s . A number of m u l t i p l e t s i n As IV have been e s t a b l i s h e d by K. R. Rao (24), w h i l e Sawyer and Humphreys (25) have l o c a t e d a few of the deepest c o n f i g u r a t i o n s of As V. Mack (17) was able t o i d e n t i f y 14 l e v e l s i n As V I , and h i s work was l a t e r p a r t i a l l y confirmed by Kruger and Shoupp (15). Other s t u d i e s of a r s e n i c i n c l u d e the work of Tolansky (29) and A. S. Rao (21) who measured i n t e r f e r o m e t r i c a l l y the hyperfine s t r u c t u r e of many As I I l i n e s . The r e s u l t s o f the two papers are e s s e n t i a l l y the same although they d i f f e r on the s t r u c t u r e assigned t o f o u r of the l i n e s . L a t e r Green and Barrows (6) measured the Zeeman e f f e c t s of s e v e r a l l i n e s , most of which belonged to As I I , but only about h a l f of which were c l a s s i f i e d . Murakawa and Suwa (22) have a l s o observed h f s . p a t t e r n s i n As I I . Both the Zeeman data and the h f s . observations support i n l a r g e p a r t the e a r l y a n a l y s i s of A. S. Rao. 6 CHAPTER I I THEORY 1. General Theory of Atomic Spectra The general theory of atomic spectra and i t s i n t e r p r e t a t i o n i n terms of the vect o r model i s so w e l l known t h a t there i s no need to r e -produce i t here. The reader i s r e f e r r e d to the t e x t s of P a u l i n g and Goudsmit (25), Herzberg (9) , or White ( 4 l ) . We s h a l l merely summarize b r i e f l y a number of the more important r e s u l t s which are u s e f u l to the e x p e r i m e n t a l i s t i n es t i m a t i n g the p o s i t i o n s of unknown l e v e l s . (a) n* Sequences The basis of a l l spectroscopic r u l e s i s the Bohr frequency r e l a t i o n which s t a t e s t h a t the frequency V m n of a s p e c t r a l l i n e may be represented as the d i f f e r e n c e between two energy l e v e l s Wm and Wn thus: _ Wm ~ w n *mn ~ h (where h i s Plank's constant) v I n terms of wave numbers t h i s becomes T m - T n -> *mn = cm t (1.1) where T m, T n are u s u a l l y c a l l e d term values, or terms. We may w r i t e n* R l! T* * TZ~=& (1*2) where R i s the Rydberg constant f _ Me J . V c h ' / Zp = e f f e c t i v e nuclear charge ( = 1, 2, ... f o r a r c , 1st spark, ... spectra) n = p r i n c i p a l quantum number n* =\u00E2\u0080\u00A2 e f f e c t i v e quantum number cTn = quantum defec t A s e r i e s of terms w i t h the same L, J , and n i n c r e a s i n g by in t e g e r s con-s t i t u t e a R i t z s e r i e s , or an \"n* sequence\". The common method of s e t t i n g up absolute term values i s to assume t h a t a n d ( b) i n t e r c o n f i g u r a t i o n p e r t u r b a t i o n s are l i k e l y to d i s t u r b the s e r i e s . Shenstone and R u s s e l l (37) have studied the case when a s e r i e s i s perturbed by a l e v e l from another e l e c t r o n c o n f i g u r a t i o n . The R i t z formula (1.2) may be w r i t t e n i n the form where/*, o< are negative constants and |<='/U+ }) -MA i 1) . 8(8/ 1) + 8.(8. *1) - 8,(8, V 1) - A i K i i 1) 28(8 + 1) \u00E2\u0080\u009E D ( A + l\-J'(f> i D 3 ( s t l ) + aAsttP - 8,(8, *1) + 21(1 + 1) ' 2s(s + 1) (1.15) f where A , &2 e i n t e r a c t i o n constants of atom core and added e l e c t r o n r e s p e c t i v e l y \u00C2\u00A3,?s, - quantum numbers of atom core \u00C2\u00A3 8X -quantum numbers of added e l e c t r o n . a ' Equation (1.15) i s u s e f u l f o r e s t i m a t i n g A from known A i n the next A higher i o n . With departures from L - S coupling (1.12) ceases to be t r u e . 12 I f we consider f o r a moment the a p p l i c a t i o n of (1.11) and (1.12) to a R i t z s e r i e s we see that the consecutive f i n e s t r u c t u r e con-st a n t s should vary as n* 3 . Hence f o r values of n* between say J and 6 \"a\" roughly halves from one member t o the next. This i s a simple \" r u l e of thumb\" method f o r q u i c k l y e s t i m a t i n g \"a\", p a r t i c u l a r l y i f the valueB of n* are somewhat u n c e r t a i n . ( f ) S e l e c t i o n Rules The number of a l l p o s s i b l e d i f f e r e n c e s between the terms of an atom i s f a r greater than the number of t r a n s i t i o n s observed because of the operation of s e l e c t i o n r u l e s . Considering only e l e c t r i c d i p o l e r a d i a t i o n there are two c h i e f r u l e s which hold independently of the st a t e of co u p l i n g . We may c h a r a c t e r i z e a l l l e v e l s as e i t h e r odd or even depending upon whether the sum of the i n d i v i d u a l e l e c t r o n quantum numbers i n the c o n f i g u r a t i o n g i v i n g r i s e to the l e v e l s i s odd or even. \"Laporte's r u l e \" then s t a t e s t h a t t r a n s i t i o n s between two odd or two even terms are for b i d d e n . The second r u l e of wide g e n e r a l i t y places r e s t r i c t i o n s on the change i n J between two l e v e l s . We f i n d A J = 0,11 (0 0 ) . Many other r u l e s may be formulated f o r s p e c i a l c o u p l i n g cases as the f o l l o w i n g f o r L - S c o u p l i n g : A S \u00C2\u00AB 0 ( i . e . i n t e r c o m b i n a t i o n l i n e s are forbidden) 4 I \u00C2\u00AB 0, i 1. The appearance of forbidden l i n e s i n a spectrum u s u a l l y i n -d i c a t e s one of f o u r p o s s i b i l i t i e s , namely: ( i ) departure from an assumed cou p l i n g case 15 ( i i ) occurrence of m u l t i p o l e r a d i a t i o n (other than e l e c t r i c d i p o l e ) ( i i i ) presence of e x t e r n a l e l e c t r i c or magnetic f i e l d s ( p o s s i b l y pro-duced by neighbouring atoms - i n t h i s case g i v i n g \"enforced d i -pole r a d i a t i o n \" ) ( i v ) p e r t u r b a t i o n s - causing a sharing of p r o p e r t i e s between two or more s t a t e s . (g) I n t e n s i t y Sum Rule The most widely a p p l i e d and probably the most u s e f u l r u l e regarding the i n t e n s i t i e s of observed l i n e s i s the Burger - Dorgelo -Or n s t e i n sum r u l e . I t s t a t e s t h a t the sum of the i n t e n s i t i e s of a l l the l i n e s of a m u l t i p l e t which belong to the same i n i t i a l or f i n a l s t a t e i s p r o p o r t i o n a l to the s t a t i s t i c a l weight (2J 1) of the i n i t i a l or f i n a l s t a t e r e s p e c t i v e l y . This r u l e by i t s e l f i s i n s u f f i c i e n t t o determine \u00E2\u0080\u00A2formvli* the r e l a t i v e i n t e n s i t i e s w i t h i n a m u l t i p l e t . C o r r e c t i n t e n s i t y ^ f o r L - S co u p l i n g have been derived both c l a s s i c a l l y and quantum mechanically and may be found i n any standard t e x t . Tables based on these formulae g i v -i n g the expected r e l a t i v e i n t e n s i t i e s i n most m u l t i p l e t s are a v a i l a b l e i n White ( 4 l , pp. 439) or Condon and S h o r t l e y (4, pp. 2 4 l ) . Two p o i n t s worth n o t i n g a r e : ( i ) the components f o r which J and L a l t e r i n the same manner are more intense than those f o r which they a l t e r i n opposite d i r e c t i o n s . ( i i ) the components a r i s i n g from l a r g e J values are more intense than those f o r small J . 14 (h) Zeeman E f f e c t Each energy l e v e l of an atom c h a r a c t e r i z e d by a p a r t i c u l a r v a l u e of J i s (2J + 1) - f o l d degenerate. The degeneracy may be r e -moved by the a p p l i c a t i o n of an e x t e r n a l magnetic f i e l d , g i v i n g r i s e t o the Zeeman e f f e c t . I f WQ be the energy of a p a r t i c u l a r l e v e l , then the energies W of the components i n t o which i t i s s p l i t by the magnetic f i e l d H are given by W \u00C2\u00AB WQ + hwMg , (1.14) where M = magnetic quantum number ( = J , J \u00E2\u0080\u0094 1, \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 > \u00E2\u0080\u0094 J) g \u00E2\u0080\u00A2=\u00E2\u0080\u00A2 Lande g- f a c t o r h\" = Planck's constant Cjj = Larmor p r e c e s s i o n freuency = e H kTTmQ c m Q= e l e c t r o n mass. The \"normal\" Zeeman e f f e c t , as opposed to the more general \"anomalous\" Zeeman e f f e c t , i s simply the s p e c i a l case of the above f o r which g = 1. For., ^ ny\u00E2\u0080\u009E l e v e l \u00E2\u0080\u0094 0 < g \u00C2\u00A3 2 , Hence we see t h a t each term s p l i t s i n t o (2J + 1) e q u a l l y spaced l e v e l s . The value of g c h a r a c t e r i s t i c of S, L, J i s d i f f e r e n t f o r d i f f e r e n t c oupling schemes. For the p a r t i c u l a r case of L - S coup-l i n g values of g have been t a b u l a t e d (14) f o r a l l terms o r d i n a r i l y appearing. The c a l c u l a t i o n s are s l i g h t l y more d i f f i c u l t i n other schemes. Anr i m p o r t a n t ; : r e g u i i e i n l t h i s i c o n n e c t d o f l ' jhofrfisvgr i s P a u l i ' s g - sum r u l e which s t a t e s t h a t f o r a l l l e v e l s a r i s i n g from a given e l e c t r o n c o n f i g -u r a t i o n the sum of the g - f a c t o r s f o r terms w i t h the same value o f J i s 15 a constant independent of the coupling scheme. S e l e c t i o n r u l e s are a l s o a p p l i c a b l e i n Zeeman m u l t i p l e t s , namely A M - 11, 0 ( 0 - ^ 0 i f A J = 0 ) . I f observations be c a r r i e d out i n a d i r e c t i o n perpendicular t o the f i e l d then those components f o r which A M = 0 are p o l a r i z e d p a r a l l e l to the f i e l d (jf- components), and those f o r which A M =\u00E2\u0080\u00A2 \u00E2\u0080\u0094 1 are p o l a r i z e d per-p e n d i c u l a r to the f i e l d ( cr-components). In the case when an assumed co u p l i n g scheme i s s t r i c t l y a p p l i c a b l e a completely r e s o l v e d Zeeman p a t t e r n g i v e s unequivocal evidence as to the S, L, J values of the term between which i t a r i s e s . Even i n the usual case when the p a t t e r n i s i n -completely r e s o l v e d and the c o u p l i n g i s unknown,extremely v a l u a b l e i n -f o r m a t i o n may be obtained, e s p e c i a l l y w i t h the a i d of the sum r u l e . 2. Theory of Complex Spectra The quantum theory of many e l e c t r o n spectra assumes as a f i r s t approximation t h a t the atomic e l e c t r o n s move i n a c e n t r a l f i e l d and do not i n t e r a c t w i t h one another. The Hamiltonian f o r t h i s case may be w r i t t e n N J 1 1 Ho.\" ( 2 7 : P i * U < r i > j ( 2 ' ^ i =1 / where r^= distance of i t h e l e c t r o n from the nucleus \"p*^ = momentum of i t h e l e c t r o n j*. = reduced mass of e l e c t r o n p l u s nucleus U(r^) = c e n t r a l f i e l d p o t e n t i a l N s number of e l e c t r o n s . Although an e x p l i c i t form f o r U(r) w i l l not be r e q u i r e d , i t i s o f t e n estimated by t r e a t i n g each e l e c t r o n as moving i n a Coulomb f i e l d due 16 t o the nucleus and the (N - 1) other e l e c t r o n s . By u t i l i z i n g the p r i n c i p l e of screening we are l e d to U(r) of the form U ( r ) ^ - 2 s \u00E2\u0080\u0094 + C ( f o r r small) r ( Z - N - f r l ) e * ' v ^ - \u00E2\u0080\u00A2\u00C2\u00BB \u00E2\u0080\u0094 \u00E2\u0080\u00A2 \u00E2\u0080\u0094 1 \u00E2\u0080\u0094 ( f o r r l a r g e ) . These may be c o r r e l a t e d r e s p e c t i v e l y w i t h the p e n e t r a t i n g and non-p e n e t r a t i n g o r b i t s of the v e c t o r model treatment. The i n t e r a c t i o n s between the e l e c t r o n s , c h i e f of which are the Coulomb e l e c t r o s t a t i c f o r c e s and the magnetic f o r c e s between o r b i t a l and s p i n angular momenta., are considered as p e r t u r b a t i o n s on H Q. The energy due t o the f i r s t of these i s N . i N i l i \u00E2\u0080\u00A2> j -1 v J / where r ^ j distance between i t h and j t h e l e c t r o n s . N e g l e c t i n g the i n t e r a c t i o n between the s p i n of one e l e c t r o n and the o r b i t o f another we may w r i t e f o r the magnetic energy N ^ \u00C2\u00A3 a ( r i ) s\u00C2\u00B1 i * 1 Hence the t o t a l Hamiltonian becomes = = J f e X - \u00E2\u0080\u0094 + a < r i > 4 \u00E2\u0080\u00A2 M The p e r t u r b a t i o n p o t e n t i a l i s taken to be H' \u00C2\u00AB H - HQ H ' * } + a ( r i ) A - \" i \" u ( r i i = l ( r i i * 3 =1 J2- (2.2) i > 2 =1 \" i j (2.3) 17 i . e . S hrodinger 1s equation f o r the unperturbed case i s H 04? - E > i - 1 L / ) (2.4) Obviously i f we choose ^ to be a product of one-electron wave f u n c t i o n s the v a r i a b l e s i n (2.4) may be separated. We denote a one-electron wave f u n c t i o n by ^ ^ ( a 1 ) , where a^ - represents a set of four quantum numbers necessary to s p e c i f y the s t a t e of motion of a s i n g l e e l e c t r o n , e.g. we might take a* = ( n , / , m^ , m^). Then w r i t e N (2.5) Because of the i n d i s t i n g u i s h a b i l i t y of the e l e c t r o n s the sets of quantum numbers a^ - may be a s s o c i a t e d i n any way w i t h the e l e c t r o n s 1, 2, ... N, and so may j u s t as w e l l be w r i t t e n as a l i n e a r combination of a l l products of the type (2 .5) , of which there w i l l be N J. By the P a u l i p r i n c i p l e must be antisymmetric w i t h respect to interchange of any two e l e c t r o n s . The only wave f u n c t i o n s a t i s f y i n g these c o n d i t i o n s may be represented i n determinantal form thus: *,(&') A t ( a ' ) \u00E2\u0080\u00A2 \u00E2\u0080\u00A2 - * K ( a ' ) ^ ( a N ) ^ A ( a \u00C2\u00AB ) . . . ^ ( a * ) (2.6) where \u00E2\u0080\u0094L_ i s a n o r m a l i z i n g f a c t o r and A represents the complete Y~NT ordered set of one e l e c t r o n quantum numbers a , a\"*, . . . a^. Our problem i s then to solve the equation H a ( r ^ ) / ^ . s^ i s of t h i s form, i =1 N For an operator Y of the form Y - j f y ( i , j ) Condon and i > 3 - l S h o r t l e y show t h a t the diagonal elements become N d r ^ d r j (A I T / A ) - J f / f i T i ( a k ) u j ( a t ) y ( l f J ) u i ( a k ) u 3 * C a H k>t * l i / ' - J J u i ( a I e ) S j ( a t ) y ( i , J ) u i ( a t ) u j ( t k ) d r ^ r j J (2.9) where again dr^, d r j i n c l u d e summation over the s p i n coordinates. The two terms i n (2.9) are r e s p e c t i v e l y the d i r e c t and exchange i n t e g r a l s . I f we denote them by J , K we may w r i t e J ( a k , a*) - ( a ^ a ^ y C l . j ) / a k a*) (2.10) K ( a k , a ^ = ( a * a t / y ( i , j ) / a* a k ) N r. and (A | Y | A) = ^ { J ( a k , a t ) - K ( a k , a 1 ) k>t--l l J N * The Coulomb operator 2 \u00E2\u0080\u0094 \u00E2\u0080\u0094 i s of the form Y. The one e l e c t r o n wave f u n c t i o n s u^ c o n s i s t of a product of a r a d i a l p a r t and an angular p a r t , the l a t t e r , being simply the s p h e r i c a l harmonics. The operator \u00E2\u0080\u0094 i _ may be expanded i n terms of Legendre r i j polynomials thus I r - k k^O where r i < r j and & i s the angle between r ^ and r - j . Hence the matri x x elements (A / \ A) may be w r i t t e n as a r a d i a l i n t e g r a l (depending o n l y on n^, ! /) m u l t i p l i e d by an angular i n t e g r a l (depending only on A \u00C2\u00BB m \u00C2\u00B1) \u00E2\u0080\u00A2 The former depends on our i n i t i a l choice of the c e n t r a l f i e l d ; the l a t t e r may be c a l c u l a t e d e x p l i c i t l y . F i n a l l y then f o r the e l e c t r o -s t a t i c i n t e r a c t i o n the i n t e g r a l s J , K of equation (2.10)become 20 J ( a , b) = / * k ( 7 a ma,/b m b ) F k ( n a y a , n b / b ) k = 0 (2.11) K(a, b) = / ( m s a , m s b) ^ / f k ( / a m a , / b m b ) G k ( n a / S nb/>) k -0 k k k k where o( ,AT are the angular i n t e g r a l s , Fr , G are the r a d i a l i n t e g r a l s , and a, b replace a k , a^ of (2.10). Due to s p i n c o n s i d e r a t i o n s the K f u n c t i o n s v a n i s h except f o r p a i r s of e l e c t r o n s w i t h p a r a l l e l spinsr, and so a kronecker d e l t a appears i n K(a, b ) . The c o e f f i c i e n t s , < k , ^ k were f i r s t c a l c u l a t e d by S l a t e r (J8) and and are a l s o t a b u l a t e d by Condon and Shortley (4, pp. 178 f f . ) . The r a d i a l f u n c t i o n s F k , G k are known as the S l a t e r i n t e g r a l s , and are a b s o l u t e l y fundamental to a q u a n t i t a t i v e knowledge of atomic s p e c t r a . (a) L - S Coupling We f i r s t consider the case when the Coulomb i n t e r a c t i o n i s much greater than the s p i n - o r b i t i n t e r a c t i o n . This s i t u a t i o n was f i r s t i n v e s t i g a t e d by R u s s e l l and Saunders u s i n g the v e c t o r model treatment and so bears t h e i r name. Neglec t i n g the magnetic energy H becomes N i N i *1 L r * ) i > j =1 r i 3 The f i r s t sum has the same value f o r a l l l e v e l s of a c o n f i g u r a t i o n and so we need consider only the second term. I f we w r i t e Ms - ^ m s and ML = \u00C2\u00A3 i t may be shown t h a t the secular equation f a c t o r s i n t o a chain of smaller secular equations, one f o r each value of Mg M^, i . e . there are non-diagonal components only be-tween determinantal wave f u n c t i o n s having a g i v e n Mg and ML1. These equations need not be solved d i r e c t l y . Instead we made use of the diagonal sum r u l e which says t h a t the sum of the roots of the equation i s equal to the^ sum of the diagonal matrix elements i n the equation. This r u l e 21 e f f e c t i v e l y allows us to solve a system of l i n e a r equations r a t h e r than a number of higher order equations i n v o l v i n g non-diagonal elements. Having obtained the r e l a t i v e energies of the l e v e l s i n t h i s manner, we may make allowance f o r the s p i n - o r b i t i n t e r a c t i o n by t r e a t i n g i t as a secondary p e r t u r b a t i o n . This gives r i s e t o the Lande i n t e r v a l r u l e as described i n s e c t i o n l . ( e ) . Condon and Sh o r t l e y (h, pp.197 f f . ) have c a l c u l a t e d the L - S energy l e v e l s f o r a great v a r i e t y of c o n f i g -u r a t i o n s . One disadvantage of the diagonal sum method i s t h a t we o b t a i n the energies but not the wave f u n c t i o n s themselves. A more important o b j e c t i o n to the a n a l y s t i s the f o l l o w i n g . I f a c o n f i g u r a t i o n gives r i s e to more than one term of a p a r t i c u l a r k i n d (as e.g. s p s'which gives p \u00C2\u00BB ) the method y i e l d s only the sum of t h e i r energies, and not t h e i r i n d i v i d u a l energies. Racah (27>b) has developed by means of tensor operators a powerful procedure which overcomes t h i s disadvantage. For the p a r t i c u l a r case of c o n f i g u r a t i o n s of the form J/ s he has w r i t t e n e x p l i c i t l y a general form f o r the energies and a p p l i e d i t to p d s ( 2 7 ,c). Such a c o n f i g u r a t i o n produces m u l t i p l e t s ' L l i m i t i n g on 'L of Jj'&nd *L l i m i t i n g on 'L of j\u00C2\u00A3 . Since i n As I I I we s h a l l be i n t e r e s t e d i n s p s' and s p p', the energies f o r these have been c a l -c u l a t e d i n e x a c t l y the same manner. The r e s u l t s a r e : s p s' : *^=F*(ns, n * s') + F\u00C2\u00B0(n'p, n \" s ' ) f - F\u00C2\u00B0(ns, n'p) - G (ns, n\" s') -jrG (n'p, n\" s') -jG (ns, n'p) r x * (2.12a) F'(ss')v.F (ps') * F (sp)+/G - ( a s 7 ) +j g' (pa') + f(}' (sp) - J G ' ( s s ' ) g'(ps') - J G ^ s s ' ) G'(sp) - ^ G ' ( p s ' ) g 'C s p ) ] * 22 B P p'\u00C2\u00AB \"S - F\u00C2\u00B0 V- f f F * ( p p ' ) - J o'(sp) -JG'(B P') - o'Cpp') - \u00C2\u00A3 G ( P P ' ) * S , V - F \u00C2\u00B0 * 5 p J ( p p ' ) i f # 0 f I ( . p ) ^ G \ S P ' ) * / V ( p p ' ) * g G*(pp')/* - ^ G'(sp) G'(sp') - J[G'(S P) -f G'(sp')] ^ ' ( p p ' ) * -\u00C2\u00A3 G V ) ] ] T ( 2 . 1 2 b ) *P = F\u00C2\u00B0 - \u00C2\u00A3 F * -JO'(BP) -^G'(sp') + G ' - ^ G 2 a p / p ' = F ' - X F ^ i / ^ G ' ^ s p ^ G ' ^ s p ' ) + ( G # - \u00C2\u00A3 G V -^G'(BP) B'(.p')^Ia'(\u00C2\u00BBp) * o W ) ] (O# ' D = F' ^ F* - JG'(B P) -JG'(Bp') - G\u00C2\u00B0 - X G' T>, D {fa (sp) G (sp ) + (G + + G ) - ^ G'(BP) G'(BP') - ^/G'(BP) * G'(B P')J ( G % ^ G')J a where F * = F*(sp) + F*(sp') + F\"(pp'). Note t h a t f o r the two doublets i n each case the negative square root g i v e s the term l i m i t i n g on That l i m i t i n g on 'L i s x I denoted by L . (b) j - j Coupling In t h i s approximation we solve the s e c u l a r determinant subject to the c o n d i t i o n t h a t the s p i n - o r b i t i n t e r a c t i o n i s large and the Coulomb one s m a l l . The matrix elements then depend on H of the form H - \ f \" U(rO + a ( r i ) l v 7t } i = 1 J A f t e r s o l v i n g the equations as before, the a d d i t i o n of a weak e l e c t r o -s t a t i c energy i s considered. The r e s u l t s of such c a l c u l a t i o n s may be found i n Condon and Sho r t l e y (4, pp.259 f f . ) . 25 (c) j - j Coupling Besides the two previous cases we consider ( j -y\u00C2\u00A3) c o u p l i n g . This occurs when the Coulomb f o r c e s are weak r e l a t i v e t o the s p i n -o r b i t i n t e r a c t i o n of the parent i o n , but are strong r e l a t i v e t o the s p i n c o u p l i n g of the e x t e r n a l e l e c t r o n . In terms of the vector model we w r i t e (2.15) and K + s = J -> where j = t o t a l angular momentum of the parent i o n -> _^ Jl , s = o r b i t a l and s p i n angular momentum of added e l e c t r o n . T h i s i s f a i r l y c l o s e l y r e l a t e d to ( j - j ) coupling* Racah (27,d) shows t h a t f o r ( j - J) c o u p l i n g the exchange i n t e g r a l s are n e g l i g i b l e , i . e . G* F f o r a l l k. The general appear-ance of a c o n f i g u r a t i o n i s a set of doublets. He develops formulae f o r the c o e f f i c i e n t s of F** and f o r the g f a c t o r s of the l e v e l s . Since these l a t t e r w i l l be req u i r e d i n the a n a l y s i s of As I I we have c a l c u l a t e d them e x p l i c i t l y f o r two c o n f i g u r a t i o n s . The r e s u l t s are given i n Table I . \ Table I t Lande g Fact o r s i n ( j -J ) Coupling d: \ j K 0 1 2 5 4 5, - * 2* .825 1.500 .755 l . l l l 1 2 2k 5 i 0/0 1.555 .855 1.500 .978 1.270 1.056 1.250 sum o/o 5.000 4.555 5-417 1.250 24 Table I (continued) f : \ v J K \ . 1 2 5 4 5 j , = s 2 | 5 i .889 1.206 .821 1.083 , = 5/2 1* 2 | .500 1.100 .844 1.175 .964 1.194 1.022 1.200 sum .500 2.835 4.166 5.500 1.200 The energy l e v e l s to be expected i n extreme ( j -jt) c o u p l i n g f o r the c o n f i g u r a t i o n pf have a l s o been c a l c u l a t e d and are l i s t e d below. K 5 3 4 2\u00C2\u00A3 2 . 5 5 , * 4 , 5 energy F - a t? \u00C2\u00B0 , a 12 ff' F + 2 \" 7 5 F 2 75 , (2.14) (d) Intermediate Coupling In most a c t u a l cases the energy l e v e l s o f atoms l i e somewhere between the l i m i t i n g approximations considered above. In-order to ob-t a i n a comparison between the observed and p r e d i c t e d terms we must solve the s e c u l a r determinant n e g l e c t i n g n e i t h e r the magnetic nor the e l e c t r o s t a t i c i n t e r a c t i o n s . The computations become much more d i f f i c u l t . 25 The f i r s t t o consider such a s i t u a t i o n was Houston (10) who c a l c u l a t e d the energies and g - f a c t o r s f o r a two e l e c t r o n c o n f i g u r a t i o n c o n s i s t i n g of one s and one a r b i t r a r y e l e c t r o n . Many workers extended the method, or i n Condon and S h o r t l e y (4, pp.268 f f . ) . To c a l c u l a t e the a c t u a l energies i n intermediate c o u p l i n g the e l e c t r o s t a t i c energies as found i n (a) must be added to the appropriate diagonal elements of the matrices f o r the s p i n - o r b i t i n t e r a c t i o n . (These l a t t e r must of course be i n the SLJM scheme.) The r e s u l t i n g s e c u l a r determinants, of which there i s one f o r each d i s t i n c t value of J i n a given c o n f i g u r a t i o n , must be solved. For the simpler c o n f i g u r -a t i o n s Johnson (7) has w r i t t e n e x p l i c i t s o l u t i o n s , while f o r the more complex ones he has l e f t the s o l u t i o n s i n determinantal form. Since i n the former case many e r r o r s ( t y p o g r a p h i c a l and otherwise) appear i n h i s r e s u l t s , and since even i n the l a t t e r case an e x p l i c i t s o l u t i o n i s use-f u l , we s h a l l reproduce here the energy equations f o r many c o n f i g u r a t i o n s which occur i n the a r s e n i c spectra. In every example the. roots of the equations g i v e the energies r e l a t i v e to the i n d i c a t e d zero. Note are the denominators appearing i n the S l a t e r parameters (see reference and a good summary of the r e s u l t s may be found a l s o t h a t we have used the n o t a t i o n and 4, pp. 178 f f . ) . ( i ) bJj J - 1 \u00C2\u00BB y* + ( | ~ 2G,)w - aG, -Z(JL+ 1) j\u00C2\u00A3 = 0 (2.15) I f we w r i t e a l l energies i n u n i t s of a we may get f o r the 1 * ( A l l energies are r e l a t i v e t o the centre of g r a v i t y of the L, i . e . to a reference P a below ? L ). 26 Another i n t e r e s t i n g theorem regarding t h i s c o n f i g u r a t i o n i s the f o l l o w i n g . Consider the approach to ( j - j ) c o u p l i n g , i . e . G^ /v a. The m u l t i p l e t appears as shown. Let \u00C2\u00A3tk = Jk + {\u00C2\u00A3 + 1) Then (/A) 6* * 1 ' 1 f //A I f 6 * \u00C2\u00A3 A t h i s becomes or ex k - -{JZ + 1)A / Hence i f L,_ - *L, = ( i > / 1) / , (where A \u00E2\u0080\u00A2= a/2) then \"In (2 . 1 7 ) R e l a t i n g & to the s p i n - s p i n parameter G. we f i n d 2G\u00E2\u0080\u009E (from (2.15)) i . e . \u00C2\u00A3SL -1 = -1 f ( 2 i + 1) L or ' ( 2 / n ) / = 2Gjt ( i i ) p j _ : J = l i 'p, =-0 J_=_2: w* - w(6F a + 5_ a) + 6aF A - 0 J - 0; w'- w(l5F, ) - |5aF z - | a* - 0 ( i i i ) pp : Write 2G, +\u00E2\u0080\u00A2 2G - 6FA v- 2G p - 4G J ^ r - - 6F, +\u00E2\u0080\u00A2 6G, & - 9 F X + 2G. f- 11G, (2.18) (2 . 1 9 ) 27 J = 3- *Vt - 0 J - 2: w? - w*^ x - |(a,y- a , ) J / w ^ - | (a , V- -a,) ( 4 * * - ^ ) + | a ' a * J ~ {\" f ( a / * a J ^ * I * * * * * * ^ ' a y ^ + f ( a , ~ (a- / a ; ) j = 0 J j ^ _ 0 : w\" - / / - | ( a , a a ) J ^ / - | ( a , t a , ) ^ ; / ^ * ( 2 ) e J_=_l: \u00C2\u00AB \" - \u00C2\u00AB 7 / \" | ^ a / ^ a ^ j ^ w ^ - 1 ^ / 5 / ) * ZT< a ^ a * ) ( \" ^ ^ 5/) / | ( a / f- a* + ? a , a j ] \u00E2\u0080\u00A2(12^ - 7 \u00C2\u00BB - -J ( a , - a j > - |L(a ; * a J J , ' 52 52 (2.20) f \u00C2\u00A7 ( * / \" a/ ) ( a , - a j j y- ^\u00C2\u00B1|(a, y- ^ y / + Y | ( a / - a/ ) ( a , - a,)*\" - | ( 2 a / y- 2a* y- 5a, a , ) / ' - ^ ( a ' - O sum = D *\u00E2\u0080\u00A2 P + - S + D + 'P / 'S W(A) W(B) W(AB) 35 Note t h a t although the a c t u a l c o e f f i c i e n t s are undetermined f o r three values of Mg we do get r e l a t i o n s f o r the sums of the terms. These are u s e f u l f o r the f o l l o w i n g t a b l e s . Table IV: C o n f i g u r a t i o n s p s' s ms P ms m^ s m6 M S M L s p s ' m u l t i p l e t s m u l t i p l e t s from p a i r s s p s s p s' \u00C2\u00A3 i ! 2 * 1 * o l 1 2 1 8 5/2 1 2/2 0 5/2-1 *P FP *P \u00C2\u00BBp 'p 'p 's 'p 'p 's J ? i 2 1 2 _ i 2 i i 1 \" ' 2 1 2 * 1 i 1 i i sum =r P \u00C2\u00A5 P f 'P i ' p ^ i ' p *s * ' p * iy 'P I ' s f i ' s | f p f i ' p I ' P f i ' P i ' S f l ' S 'P Note t h a t of the two doublets the one i n d i c a t e d w i t h a prime l i m i t s on the s i n g l e t of the i o n . Using the r e l a t i o n i w(ABC) \u00C2\u00AB w(AB) f w(AC) w(BC) (2.7) we get from the f i r s t set i n Table IV, w( VP) = w(sp'p) + w(ss' 'S) +. w(ps''p) (2.7) Using (2.7) t o e l i m i n a t e P i n the second set of the t a b l e , and usin g (2.5), the r e s u l t s i n Table VI f o l l o w . Table V: C o n f i g u r a t i o n s p p 7 s ms P ms m^ p m3 TDji Mg ML s p p' m u l t i p l e t s m u l t i p l e t s from p a i r s s p s p' p p' l 2 * 1 * 1 5/2 2 YD 'P 'P JD 1 2 i 2 * 1 * o * o 5/2 1 5/2 l 'P 'p '^D \u00C2\u00A7'P 'p 'p '^D 1 2 II II k 1 \" 0 \" -1 * -1 \" 0 \" 1 3/2 0 \u00C2\u00BB V V sum = D +\u00E2\u0080\u00A2 P r- S 'P 'P *P P sum \u00C2\u00AB D * P S /p * p 56 Table V (continued) 8 m s P p m3 njj Mg M L s p p ' m u l t i p l e t s m u l t i p l e t s from p a i r s s p s p' p p' i \"2 1 ~ 2 ! 1 I i i 1 * 2 v P y sum = D y- D y- F 'P. y y. 'P + 'S * 'S x 'P x 'p X J ? > > x y sum c D + P x y y.'S x y The r e s u l t s i n Table VI f o l l o w from Table V e x a c t l y as before f o r s p s'. In Table V we have used x = f'p + \u00E2\u0080\u00A2\u00C2\u00A7\"'P ; y = i*P t f'P ; z = f *D +\u00E2\u0080\u00A2 -\u00C2\u00A7-'D . Table V I ; R e s u l t s f o r s p s ' and s p p 7 s p t S B p s s p P P s P 3 i P sps P *p * V 3 P 'P *- 'P , s h + 's J , P , P *- P - *s -2*8 -'p -2

6)> and the even c o n f i g u r a t i o n s 4s*4p6p, 4s i 4p4f have been e s t a b l i s h e d . In a d d i t i o n the c o n f i g u r a t i o n s 4s* 4p7p and 4s* 4p5f are t e n t a t i v e l y suggested. A few of the miscellaneous terms of Rao's work have been confirmed while s e v e r a l others have been r e j e c t e d . Many l i n e s apparently not observed by Rao have been c l a s s e d as t r a n s i t i o n s between l e v e l s e s t a b l i s h e d by him. In t o t a l , 500 l i n e s are now assigned as combinations between 54 odd l e v e l s and 35 even l e v e l s . Table V I I I i n c l u d e s a l l the l i n e s (together w i t h t h e i r o r i g i n ) t h a t have been assigned to As I I . About 15 l i n e s are doubly c l a s s i f i e d and the most probable parentage i s entered i n the t a b l e . A l l the e s t a b l i s h e d terms, t h e i r i n t e r v a l s and g- f a c t o r s are l i s t e d i n Table IX. Note t h a t i n order t o conform w i t h the format used i n \"Atomic Energy L e v e l s \" (21) the l e v e l s are not n e c e s s a r i l y l i s t e d i n numerical order. (a) I o n i z a t i o n P o t e n t i a l Using the improved wavelengths the terms e s t a b l i s h e d by Rao were f i r s t r e c a l c u l a t e d . Then by sweeping the wavelength l i s t w i t h known d i f f e r e n c e s a l a r g e number of l e v e l s were e s t a b l i s h e d and u s u a l l y a d e f i n i t e J could be assigned. The next step was t o determine the parentage of these l e v e l s . Immediately a discrepancy appeared i n the i o n i z a t i o n p o t e n t i a l assigned by Rao, f o r the newly found terms l a y i n regions deemed improbable by h i s choice of n*. The i s o e l e c t r o n i c s p e c t r a Ge I and S e l l l were of l i t t l e use i n p r e d i c t i n g terms since t h e i r analyses were very l i t t l e f u r t h e r advanced than t h a t of a r s e n i c i t s e l f . Other c o n s i d e r a t i o n s were used i n naming the s t a t e s , Zeeman data being 44 i n v a l u a b l e where a v a i l a b l e . A new i o n i z a t i o n p o t e n t i a l was c a l c u l a t e d based c h i e f l y on the 4pns s e r i e s , t h i s being the l e a s t perturbed (see l a t e r ) , and a value of 150,290 cm. ' ( =18 .6 ev.) was chosen as the best f i t . Values of n* f o r each term are included i n Table IX. Figure 2 shows Moseley diagrams f o r a few terms of the As I I sequence. (b) A p p l i c a t i o n of Intermediate and ( j -J ) Coupling Before d i s c u s s i n g the i n d i v i d u a l c o n f i g u r a t i o n s we s h a l l remark on a few po i n t s of general i n t e r e s t . Even the deep l y i n g m u l t i p l e t s do not approach (L - S) co u p l i n g . The 4pns s e r i e s i s very c l o s e to ( j - j ) co u p l i n g while the 4p4f group i s e s s e n t i a l l y ( j - J') c o u p l i n g . Intercom-b i n a t i o n l i n e s occur w i t h great frequency as would be expected and i n f a c t there seems a c t u a l l y l i t t l e d i s t i n c t i o n between s i n g l e t s and t r i -p l e t s i n t h i s respect. Rather c o i n c i d e n t a l l y the term 4p5p*Dy l i e s ex-a c t l y midway between 4s5s'p, and kaSn3^ and the two corresponding t r a n s -i t i o n s could not be re s o l v e d . ( i ) 4 8 % 2 : This c o n f i g u r a t i o n gives r i s e t o P D y S f o r which we get two l e v e l s w i t h J = 0 and two w i t h J \u00E2\u0080\u00A2= 2. By s u b s t i t u t i n g the observed energies i n (2.19) and s o l v i n g e x p l i c i t l y f o r F and a we f i n d t h a t the intermediate coupling f i t s almost e x a c t l y . Both equations g i v e e s s e n t i a l l y 2 -I the same values of the parameters, namely F =\u00E2\u0080\u00A2 33,800 cm. and a y ^ = 1650 cm.' . We conclude t h a t the l e v e l s are unperturbed and note 3 t h a t since \u00E2\u0080\u0094 i s r e l a t i v e l y small the coupling i s approaching ( j - j ) . a ( i i ) 4p^\u00C2\u00A3 s The c a l c u l a t i o n s i n t h i s case are somewhat more d i f f i c u l t . A n t i c i p a t i n g a r e s u l t i n As I I I , the l i m i t i n g value of a i s i960 cm,\"'' , GET AS II 8E III BR IV FIG. 2. MOSELEY DIAGRAM FOR AS II 45 and since the screening of the 4p e l e c t r o n has decreased c o n s i d e r a b l y from ( i ) we assume a value here of a ; = 1840. Using the r e g u l a r doublet law (1.11) we estimate a = 58O cm. . These two values together w i t h the observed energies are used i n (2 .20) to evaluate the S l a t e r i n t e g r a l s (using the sum energies f o r each value of J ) . V/e thus o b t a i n F = 8064, 0 =\u00E2\u0080\u00A2 I 8 9 I , G \u00E2\u0080\u0094 1542. Table X presents the c a l c u l a t e d and observed energies and g- f a c t o r s u s i n g these parameters. The r e s u l t s must be r e -garded as s a t i s f a c t o r y , and l i t t l e p e r t u r b a t i o n occurs. The g-sums are w i t h i n 0.01 of the t h e o r e t i c a l v alues. Table X: C o n f i g u r a t i o n 4p 5p Level Energies g-factors ' (6) obs. c a l c . obs-. c a l c . -3868 -3913 0.812 0.800 'D, -2284 -1857 0.895 0.905 -2084 -1917 1.174 1.180 'p. - 961 - 963 'p, - 18 - 397 1.589 1.405 > 0 0 1.325 1.333 'p* 1062 768 1.433 1.435 1891 I889 I.896 1.890 3194 5322 1.046 1.052 X 6591 6595 ( i i i ) 4p 6p : The c o n f i g u r a t i o n 4s^4p6p overlaps almost e x a c t l y the l e v e l s due to 4p4f and the task of separating the two i s d i f f i c u l t (and one might even be i n c l i n e d to say meaningless). However w i t h the a i d p a r t i c u l a r l y of Zeeman data the l e v e l s were f a i r l y s a t i s f a c t o r i l y i d e n t i f i e d . Note t h a t the order of terms i s a l i t t l e changed from 4p5p. The *P now appears as p a r t i a l l y i n v e r t e d , while the ^ and 'D^ have apparently been per-turbed by the corresponding terms of 4p4f. Intermediate c o u p l i n g could 46 not be a p p l i e d d i r e c t l y as three l e v e l s have not been found, namely , 3 S/ , 's^ . We o b t a i n here an example of the p r a c t i c a l a i d of intermed-i a t e c o u p l i n g . Noting t h a t F^ v a r i e s roughly as n* 3 from 4p^ t o 4p5p e x t r a p o l a t i o n gave F f o r 4p6p. a, and a., were obtained as before, G , G* estimated, and the corresponding energies c a l c u l a t e d . Since the term but few others were by t h i s time known, a rough estimate was had of the missing l e v e l s . I n view of the approximations i n v o l v e d and the h i g h p e r t u r b a t i o n s present the \"guess\" was s u r p r i s i n g l y good. ( i v ) 4p 4f : A l l l e v e l s but one were e s t a b l i s h e d , the *'DJ found being assigned t o 4p6p on the basis of the g sum r u l e . The terms designated as 3 Gr and 'G may perhaps be interchanged, but t h i s i s somewhat of an academic question. Both the *G and *F are found p a r t i a l l y i n v e r t e d . The c o n f i g -u r a t i o n was examined i n terms of ( j -\u00C2\u00A3 ) co u p l i n g . A comparison of the g-values of Tables IX and I shows e x c e l l e n t agreement on the whole. The system of doublets expected i n ( j -J ) coupling are more or l e s s present, a l l o w i n g f o r the p e r t u r b i n g e f f e c t of 4p6p. One important o b s e r v a t i o n i s the f o l l o w i n g . The set of four \"doublets\" l i m i t i n g on of As I I I occur i n j u s t the reverse of the p r e d i c t e d order. Under f u r t h e r i n v e s t -i g a t i o n of the ( j -J) formulae f o r pp i t was found t h a t the h i g h S0 ( c f . 4p5p) i s p r e d i c t e d to be a member of the deepest \" Pfx doublets\". This would seem unusual. One i s i n c l i n e d to f e e l t h a t a negative s i g n has somewhere occurred erroneously. The term *G i s d e f i n i t e l y a J =\u00E2\u0080\u00A2 J as shown by Zeeman data, yet i t combines w i t h s e v e r a l J = 1 . This may account f o r a missing l e v e l of 4p6p ( c f . Chapter V). (v) 4p 5f and 4p 7p : The terms assigned to t h i s parentage must be regarded as 47 t e n t a t i v e only. Even the J f o r each i s i n d e f i n i t e . T h e i r combinations are sporadic and perhaps beyond the t o l e r a n c e l i m i t s . The l i n e s sup-p o r t i n g these l e v e l s are l i s t e d i n Table XXI r a t h e r than Table V I I I . ( v i ) 4p n s : The three e s t a b l i s h e d s e r i e s m u l t i p l e t s give an e x c e l l e n t ex-ample of the v a l i d i t y of Houston's r e l a t i o n s , the f i r s t two members par-t i c u l a r l y being \"textbook examples\". The Js> group dfe s l i g h t l y perturbed by the o v e r l y i n g 4p6d l e v e l s , and i n f a c t a i s j u s t s l i g h t l y l a r g e r than i t s l i m i t i n g value. The values obtained f o r the parameters are: 5s: a = I850 0 ' * 3354 6s: 1924 1982 7s: 1978 2051 Using these parameters the agreement between the observed and c a l c u l -ated g - f a c t o r s i s shown i n Table XI to be w i t h i n the l i m i t s of e r r o r on the measurements of Green and Barrows (6) . Table X I : g - f a c t o r s f o r 4p 5 s a n d 4p 6s Level 4p 5s 4 P 6 s g obs. g c a l c g obs g c a l c . 1.424 1.427 1.40 1.411 p* 1.492 1.500 1.49 1.500 p. 1.075 1.073 1.11 I.O89 J 2 ( v i i ) 4s 4p and 4s 4p 4d : We w i l l consider these c o n f i g u r a t i o n s together because they e x h i b i t strong i n t e r c o n f i g u r a t i o n p e r t u r b a t i o n s . The_former group i s e s p e c i a l l y important because one would expect i t t o lead to the estab-lishment of the even c o n f i g u r a t i o n 4s4p J 5s. A l l attempts i n t h i s d i r e c -r 3 t i o n were unsuccessful however. The deep-lying S of 4s4p has been 48 only t e n t a t i v e l y i d e n t i f i e d by i t s u l t r a - v i o l e t combinations w i t h 4s 4p . The i s found to have a small i n t e r v a l f a c t o r as expected, and i s p a r t i a l l y i n v e r t e d . The \"^P of 4p4d i s a l s o p a r t i a l l y i n v e r t e d . We may note t h a t the g sum f o r J = 1 of 4p4d i s l a r g e r than t h e o r e t i c a l . This has been thought due t o the p e r t u r b a t i o n s between the two 'P 's,. but the p o s s i b i l i t y e x i s t s t h a t these two should be interchanged. A strong mutual r e p u l s i o n between the terms r e s u l t s i n t h e i r being h i g h l y d i s -placed from intermediate coupling p o s i t i o n s . The p e r t u r b a t i o n r e s u l t s i n a mixing of wave f u n c t i o n s , and hence the strong combinations 4s4p ? 'D - 4p4f, 4p6p. The terms *P 3>fJ *Sf of 4s4p ? have been so named because of t h e i r combining p r o p e r t i e s - the t r a n s i t i o n P, t o 4p5p Se i s strong. One could again consider interchanging the names. The l e v e l s can h a r d l y belong to the nd or ns s e r i e s . The two e l e c t r o n t r a n s i t i o n s 4s4p'? - 4p4f, 4p6p are a d i r e c t r e s u l t of the sharing of p r o p e r t i e s between 4s4p* and 4p4d. O r d i n a r i l y they could be forbidden. The per-t u r b a t i o n i s a maximum f o r the 'D3'S as noted. No acceptable f i t could be obtained f o r e i t h e r c o n f i g u r a t i o n i n intermediate c o u p l i n g . The g f a c t o r s f o r 4p4d may be compared w i t h the ( j - \u00C2\u00A3 ) values but there i s no s t r i k i n g resemblance. They are i n t h i s case c l o s e r to the values f o r L - S co u p l i n g , ( v i i i ) 4p 3d : The p e r t u r b a t i o n s evident i n 4p4d were not n e a r l y as marked i n 4p5d and so the l a t t e r i s more r e p r e s e n t a t i v e of the nd s e r i e s . . Some l i t t l e confusion arose i n the assignment of R u s s e l l Saunders names to the va r i o u s members and the scheme f i n a l l y chosen i s subject t o the personal p r e j u d i c e s of the w r i t e r . I n c o n s i s t e n c i e s i n the g values arose, and o c c a s i o n a l l y the observed combinations were i n s u f f i c i e n t to a s s i g n a 4 9 d e f i n i t e J . On the basis of g the names *D and should be i n t e r -changed, but a l l other f a c t o r s p o i n t to the n o t a t i o n used. The \"*P i s completely i n v e r t e d as p r e d i c t e d f o r L - S co u p l i n g and the 3D i s p a r t i a l l y so. Some evidence of ( j ~J ) coupling i s seen i n both g values and p a i r i n g of l e v e l s . Because of these r e l a t i v e u n c e r t a i n t i e s i n t e r -mediate c o u p l i n g was not a p p l i e d , ( i x ) 4p 6d : A number of the l e v e l s i n 4p6d s t i l l remain u n i d e n t i f i e d . The onl y complete m u l t i p l e t found was *D, and i t i s again p a r t i a l l y i n v e r t e d . The l e v e l *F i s probably not r e a l , w h i l e 3 Po seems severely out of pos-i t i o n . Two other odd l e v e l s were l o c a t e d . One i s assigned the parent-age 4p8s P , while the other i s probably due t o 4p5g. (c) C a l c u l a t i o n of S l a t e r Parameters i n I s o e l e c t r o n i c Spectra By comparing the c o n f i g u r a t i o n s 4s'* 4p* and 4s''4p5p i n the As I I i s o e l e c t r o n i c sequence (Ge I , As I I , Se I I I ) an attempt was made t o de-termine r e g u l a r i t i e s i n F k , G k by a p p l y i n g the intermediate c o u p l i n g r e -l a t i o n s . I t was found t h a t \u00C2\u00A3 and G are very c l o s e l y l i n e a r f u n c t i o n s of Z i n 4p5p, i n c r e a s i n g w i t h Z. The l i n e a r i t y i s not as good f o r F\"7 i n 4p* but may s t i l l roughly apply. Since only three values f o r each para-meter are obtained these observations must be accepted w i t h r e s e r v a t i o n s . The values of G\"* are anomalous. The parameters are l i s t e d i n Table X I I . 50 Table X I I : S l a t e r Parameters i n As I I I s o e l e c t r o n i c Sequence F 4 P 5P G' o a V -F Ge I 4275 985 1000 23,500 As I I 8064 1891 1542 53,800 Se I I I 12500 2800 -1625 4o,5oo 1 ( A l l values i n u n i t s of cm.\"' ) We note the f o l l o w i n g p o i n t s . A negative value o f G i n Se I I I i s unacceptable since G k are p o s i t i v e f u n c t i o n s (27b). This i n d i c a t e s e i t h e r t h a t some of the terms are i n c o r r e c t l y e s t a b l i s h e d or t h a t strong p e r t u r b a t i o n s occur. The l a t t e r seems u n l i k e l y i n view of the l a c k of such e f f e c t s i n Ge I and As I I . The r u l e mentioned e a r l i e r t h a t F** v a r i e s as n* i n a s e r i e s i s very roughly born out. In t h i s respect the i o n i z a t i o n p o t e n t i a l quoted f o r Ge I (21) seems erroneous. Using i t one gets n* values of 1-55 a n |i 2.65 f o r 4p^ and 4p5p r e s p e c t i v e l y . This change i n quantum defect appears too great. While v a r y i n g the parameters to o b t a i n a best f i t i t became evident t h a t G* was very s e n s i t i v e t o changes i n F and G , and hence not much weight can be assigned to the values of G* quoted. (d) Theory of L i m i t s o One of the long outstanding problems i n atomic spectra i s the assignment o f the c o r r e c t l i m i t i n g term to the l e v e l s of a c o n f i g u r a t i o n . The i n t e n s i t y data now a v a i l a b l e i n As I I allows us to st a t e the probable l i m i t s f o r a few s e r i e s . A l l c o n f i g u r a t i o n s of the type 4s''4p n . / l i m i t on 4s'*4p'Jp of As I l l a n d the problem here reduces t o choosing e i t h e r or *P. f o r the l i m i t ( t h e two terms being 2940 cm.\"' a p a r t ) . We use as '1 : 5 t \u00E2\u0080\u00A2 * a b a s i s f o r our d i s c u s s i o n the f a c t t h a t terms l i m i t i n g on Vj. should x not combine w i t h those l i m i t i n g on*!^. since they lead e s s e n t i a l l y t o two e l e c t r o n t r a n s i t i o n s . Consider f i r s t the t r a n s i t i o n s 4p4d - 4p4f. The 3 J 3 l 3 3 deep l e v e l s F2 , F, , Gy , F, of 4p4f combine s t r o n g l y w i t h F , F^ , 3 3 , of 4p4d, but only r e l a t i v e l y weakly w i t h the other terms. The remaining l e v e l s i n each group combine s t r o n g l y among themselves, and intercombinations are again an order weaker. Allowance must of course be made f o r the L - S s e l e c t i o n r u l e ^ L = 0 , 1, but the e f f e c t i s s t i l l e v i d e n t . Coupled w i t h t h i s , the c h a r a c t e r i s t i c d i f f e r e n c e of 3000 cm!\"' occurs i n 4p4f between the two groups of terms. S i m i l a r c o n s i d e r a t i o n s were a p p l i e d to the combinations 4p5p - 4p4d, but the e f f e c t i s not as marked. Table X I I I i n d i c a t e s the estimated l i m i t s f o r these c o n f i g u r a t i o n s . The values of n* l i s t e d i n Table IX are based on these l i m i t s . Table X I I I : Term L i m i t s f o r 4p nj C o n f i g u r a t i o n Terms l i m i t i n g on *Px z Terms l i m i t i n g on P,x PP pd Pf 'p, \ \ X ;D, % % F; F 'F SF G r3 rx ri u y a l l others II II (e) Atomic Energy R e l a t i o n s The methods of Chapter I I , S e c t i o n 3 were a p p l i e d to 4s 4p and 4s4p J to estimate the accuracy of the approximations. The r e s u l t s were not too s a t i s f y i n g . Because of the h i g h l y perturbed nature of 3 j 4s 4p and because p of As I I I i s s t i l l unknown, no f a i r c r i t i c i s m z . z may be made f o r t h i s c o n f i g u r a t i o n . For 4s 4p on the other hand the method should be adequate. However the terms *P and S were p r e d i c t e d 52 8% too h i g h - a discrepancy l a r g e r than one might wish, but s t i l l a f a i r estimate. The D c a l c u l a t i o n i s a f f e c t e d by a h i g h l y perturbed 4s4p D i n As I I I . ( f ) A d d i t i o n a l Remarks 0 A concentrated attempt was made t o f u r t h e r extend a l l s e r i e s as w e l l as to l o c a t e 4s a 4p5g, but l i t t l e success was met. The number of u n c l a s s i f i e d l i n e s i n these regions was so great t h a t chance coincidences were innumerable. Thus i t was p o s s i b l e to set up a large number of p l a u s i b l e terms, none of which are l i s t e d (except 4p6p, 4p5f). The to l e r a n c e s are a l i t t l e g reater than one would expect and the l e v e l s are g e n e r a l l y u n s a t i s f a c t o r y . N e i t h e r could the c o n f i g u r a t i o n s 4s4p 5s & n d * 3 4s4p 5p be l o c a t e d . The former should combine s t r o n g l y w i t h 4s4p but the t r a n s i t i o n s l i e f a r i n the u l t r a - v i o l e t . The p o s i t i o n of 4s4pa 5 s can be estimated i n a number of ways and the m u l t i p l e t i n t e r v a l s can be c a l c u l a t e d from (1.13). The c o n f i g u r a t i o n i s p r e d i c t e d to appear around i o n i z a t i o n , w i t h the deep P probably a t about 15,000 cm. (a b s o l u t e ) . No s a t i s f a c t o r y terms above i o n i z a t i o n were l o c a t e d . The outstanding i n t e n s i t y assigned t o As I I l i k e l y o r i g i n a t e s i n l a r g e p a r t from the t r a n s i t i o n s 4s4p 5s - 4s4pA5p\u00C2\u00AB 5. A r s e n i c I I I Attempts to extend the a n a l y s i s of the As I I I spectrum were a l i t t l e d i s a p p o i n t i n g f o r two unexpected reasons. The terms e s t a b l i s h e d by K. R. Rao were found to be s a t i s f a c t o r y but t r a n s i t i o n s from these t o the next members of the ns, np, and nd s e r i e s were c a l c u l a t e d to l i e 55 e i t h e r i n the i n f r a - r e d or the f a r u l t r a - v i o l e t . Trouble was exper-ienced i n l o c a t i n g them. The As I I I i n t e n s i t y i n these regions of our p l a t e s was not too high. Secondly, the nd - nf and nd - np m u l t i p l e t s c o n s i s t of three l i n e s . The i n t e n s i t y of the o f f diagonal one i n the known m u l t i p l e t s i s as a r u l e very low, and so i n the next members may w e l l be missing e n t i r e l y . Thus the known d i f f e r e n c e s may not appear on the wavelength l i s t . The most important c o n t r i b u t i o n s are the establishment of the if 2 XX deep P of 4s4p by intercombinations w i t h 4s 4p P, and the extension of the 4s* ng s e r i e s to n =10. This l a t t e r was made p o s s i b l e by the i d e n t -i f i c a t i o n of 4s 5f F i n combination w i t h 4s 5d D. A s l i g h t r e v i s i o n of the i o n i z a t i o n p o t e n t i a l f o l l o w e d . Other terms l o c a t e d i n c l u d e 4s*6dJD, \u00C2\u00AB! 2 ) If 4s 6p P ( ? ) , and 4p S, g i v i n g a t o t a l of 15 new l e v e l s e s t a b l i s h e d . A l l c l a s s i f i e d As I I I l i n e s are l i s t e d i n Table XIV, while Table XV con-t a i n s the r e v i s e d energy l e v e l s . The i o n i z a t i o n p o t e n t i a l now stands a t 228,725 cm.\"' - 28 .4 ev. The doublet s e p a r a t i o n of 4s* 4f *F i s - 8 .0 cm.\"' and of 5f'*F i s - 10.5 cm.\"' . This does not f o l l o w the r e g u l a r doublet law, but i s c o n s i s t e n t w i t h other members of the i s o e l e c t r o n i c sequence. Other mult-i p l e t s i d e n t i f i e d are f a i r l y r e g u l a r . Strenuous attempts t o l o c a t e 4s4p5s and 4s4p5p were made. The i r p o s i t i o n s and i n t e r m u l t i p l e t sep-a r a t i o n s were c a l c u l a t e d by the Bacher - Goudsmit method. The l a t t e r i n t e r v a l s were a l s o evaluated f o r L - S coupling by the methods of Chapter I I , S e c t i o n 2(a). For t h i s , use was made of Ufford's assumption (27d) t h a t the r a d i a l i n t e g r a l s f o r two e l e c t r o n s are independent of the c o n f i g u r a t i o n i n which they are s i t u a t e d . Values of F k , G k from As I I and As IV were t h e r e f o r e used. Although admittedly a rough approximation 54 the two c a l c u l a t i o n s were i n good agreement, and one expects t o f i n d f -I v -I 4s4p5s P a t about 60,000 cm. (absolute) and 4s4p5p D a t about 25,000 cm . The i n t e r v a l f a c t o r s f o r the various m u l t i p l e t s were a l s o estimated by ( l . l j ) . A number of strong As I I I l i n e s s t i l l u n c l a s s i f i e d are probably t r a n s i t i o n s between these two groups. The strong combinations 4s4p P -y 4s4p5s P apparently l i e too f a r i n the u l t r a - v i o l e t (100,000 cm.\" ) to be observed on our p l a t e s (As I I I i n t e n s i t y i s low i n t h a t r e g i o n ) . The i d e n t i f i c a t i o n of the 4s np sequence i s probably hindered by strong i n t e r -3 c o n f i g u r a t i o n p e r t u r b a t i o n s . As w e l l as 6, 7p P we expect t o f i n d \u00E2\u0080\u00A2 1 * z 1 1 3 x 4s4p5s P, P and 4p P l y i n g i n the same general area. These w i l l m utually d i s t u r b each other. Moseley diagrams f o r a number of terms are p l o t t e d i n Figure 3\u00C2\u00AB Intermediate coupling formulae were a p p l i e d to the c o n f i g u r a t i o n 4 s 4 p a , but the three equations were i n c o n s i s t e n t . This i s of course due t o the strong p e r t u r b a t i o n s between the *D and *S and the corresponding doublets based on the 4s core. 4s 4d D has shared most of i t s p r o p e r t i e s w i t h 4s4p* *D. The \"forbidden\" t r a n s i t i o n s 4p* \"*D - 5p^P & r e very intense . 1 X -1 and the s e p a r a t i o n of 4p D i s 321 cm. r a t h e r than zero as p r e d i c t e d . 1 J The g a i n i n i n t e r v a l f a c t o r i s a t the expense of 4d D which has an anomalously low value. (a) Atomic Energy R e l a t i o n s The most comprehensive t e s t of Bacher and Goudsmit's r e l a t i o n has been made i n As I I I . Table XVI contains the observed and p r e d i c t e d energy l e v e l s f o r a l l m u l t i p l e t s c o n t a i n i n g s and p e l e c t r o n s . The per-centage e r r o r (given by the d i f f e r e n c e between observed and p r e d i c t e d energies d i v i d e d by the observed) i s a l s o l i s t e d . _ l I I I\u00E2\u0080\u0094 OA I OE II A8 III 8E IV FIG.3. M O S E L E Y DIAGRAM FOR AS III 55 Table XVIt Test of Atomic Energy R e l a t i o n s Term Observed Energy C a l c u l a t e d Energy % e r r o r 4s4p* V 161535 I63915 cm.\"' 1.47 ?D 143228 125286 12.53 AP 115801 112471 1.17 120924 118261 2.20 4s 4p 2P 226770 230069 1.45 5P *P 96790 IO2698 6.10 5s s 122056 122495 0.58 6s *s 65841 68000 2.28 4 P J *s 6206I 54506 12.17 With three exceptions the r e s u l t s are extremely good. As alr e a d y noted 4s4p* *D i s h i g h l y perturbed and so an accurate p r e d i c t i o n i s u n l i k e l y . I t may w e l l be, e s p e c i a l l y i n the l i g h t of these r e s u l t s , t h a t 4p S i s i n c o r r e c t l y named. 5p P has a l s o a r e l a t i v e l y l a r g e de-v i a t i o n . E r r o r s of l e s s than 1 - 2 % should not be expected because of the approximations i n v o l v e d i n the theory. P a r t i c u l a r l y s a t i s f y i n g i s the f a c t t h a t we are d e a l i n g w i t h only a 2 e l e c t r o n spectrum. The accur-acy should increase as more e l e c t r o n s are added because more experimental data i s a v a i l a b l e . Although t h i s d i d not happen i n As I I , the c r i t i c i s m may be un j u s t since only one c o n f i g u r a t i o n could be t e s t e d . On the ba s i s of Table XVI the p r e d i c t i o n s of 4s4p5s and 4s4p5p may be expected to be f a i r l y accurate. 4. A r s e n i c IV L i t t l e a d d i t i o n to the As I? spectrum has been p o s s i b l e on the ba s i s of the o b s e r v a t i o n a l m a t e r i a l . The l e v e l s e s t a b l i s h e d by K. R. Rao seem g e n e r a l l y to be c o r r e c t and they have been r e c a l c u l a t e d here w i t h g r e a t e r accuracy. A number of h i s s i n g l e t s appear questionable and a more s a t i s f a c t o r y 4s5d D was found a t the p o s i t i o n i n d i c a t e d i n Table 56 X V I I I . 4s5d Dj was a l s o r e l o c a t e d . The term 4s4d i n v o l v e s a number of l i n e s w i t h more the character of lower e x c i t a t i o n , but s i n c e no s a t -i s f a c t o r y l e v e l could be found to replace i t we have l e t i t stand. 4s6s 'So and p a r t i c u l a r l y 4s4f F, of Rao are improbable. The m u l t i p l e t 4s6p'p has t e n t a t i v e l y been e s t a b l i s h e d i n combination w i t h 4s5d. The l i n e s i n v o l v e d c e r t a i n l y a r i s e from As IV but the d i f f e r e n c e s are a l i t t l e o utside the d e s i r e d t o l e r a n c e l i m i t s . Since the l i n e s are weak and d i f f u s e , appear only on the prism p l a t e s , and occur i n the v i s i b l e r e g ion, they may w e l l be i n e r r o r by t h i s amount. However, the i n t e r v a l f a c t o r f o r the m u l t i p l e t i s a l s o s l i g h t l y s m a l l . A l l c l a s s i f i e d l i n e s are l i s t e d i n Table XVII. Intermediate c o u p l i n g formulae have been a p p l i e d to a l l c o n f i g -u r a t i o n s . The two J =-0 l e v e l s of h-p* give good values of the parameter^ but the J -2 l e v e l s are i n c o n s i s t e n t . This i s due to the strong per-t u r b a t i o n between 4p and 4s4d . The former i s pushed very high. Condon and S h o r t l e y (4, pp.J66) consider a s i m i l a r e f f e c t i n 3 p J of Mg I . The c o u p l i n g i n a l l other c o n f i g u r a t i o n s i s very c l o s e l y R u s s e l l -Saunders, afieevidenced by the f a c t t h a t G k>a. Hence the formulae f i t c l o s e l y . The t r i p l e t s are a l l r e g u l a r L - S m u l t i p l e t s . A p e c u l i a r i t y of the spectrum i s the appearance of the s i n g l e t s deeper than the t r i -p l e t s i n the nd s e r i e s . A l l members of the i s o e l e c t r o n i c sequence ex-h i b i t the same e f f e c t , as do the spectra J s j d . The i n t e n s i t y formulae of Chapter I I , S e c t i o n 1 (g) are a l s o very c l o s e l y obeyed. 5. A r s e n i c V The a n a l y s i s of As V has been c o n s i d e r a b l y extended i n the 57 present work, w i t h the c o n f i g u r a t i o n s 5p> 5f\u00C2\u00BB 5d, 5g\u00C2\u00BB 6s having been i d e n t i f i e d . Only four c l a s s i f i e d l i n e s have been observed on our own p l a t e s , namely the s e n s i t i v e t r a n s i t i o n s 4s - 4p and 5 s ~ 5p\u00C2\u00BB A l l others are taken from the published values of Queney (26). No 4f*F s p l i t t i n g could be detected on the basis of Queney's l i n e s . This seems unusual i n view of the r e l a t i v e l y l a r g e 4f i n t e r v a l s i n the e a r l i e r a r s e n i c s p e c t r a . A l l other members of the i s o e l e c t r o n i c sequence a l s o have a 4f separation. One would expect an i n t e r v a l of 15 t o 20 cm.\"'. The 5 ^ ^ s e l e c t e d shows a separation of 16 cm\"' and i s e r e c t . The F's i n the i s o e l e c t r o n i c spectra seem to be e r e c t and i n v e r t e d i n a random f a s h i o n . Tables XIX and XX c o n t a i n the c l a s s i f i e d l i n e s and observed terms r e s p e c t i v e l y . Figure 4 shows a Moseley diagram f o r 5P P. The Z^ divergence of the r e g u l a r doublet law i s depicted. 9 CU I ZN II 6A III 6 E IV A 3 V FIG.4. MOSELEY DIAGRAM FOR AS V 58 CHAPTER V Re aume' Of the 1500 l i n e s appearing on our p l a t e s more than 50% are now c l a s s i f i e d i n the spark spectra. These comprise approximately 90% of the t o t a l i n t e n s i t y . Estimates of the probable o r i g i n of the out-standing i n t e n s i t y have been made i n the previous chapter. The strong l i n e s remaining u n c l a s s i f i e d are f o r the most p a r t l o c a l i z e d t o small groups. A l l these prominent l i n e s were i n v e s t i g a t e d and a t a b l e c o n s i s t -i n g of a l l p o s s i b l e d i f f e r e n c e s among them was drawn up. No r e g u l a r i t i e s were discovered i n t h i s way, and i n f a c t no d i f f e r e n c e appeared more than twice ( w i t h i n t o l e r a n c e l i m i t s ) . None of the already known d i f f e r e n c e s appeared. A l l u n c l a s s i f i e d spark l i n e s are l i s t e d i n Table XXI w i t h the probable e x c i t a t i o n of the more intense ones s p e c i f i e d . No important v i o l a t i o n of s e l e c t i o n r u l e s have been detected (except o f course L - S coupling r u l e s ) . An i n t e r e s t i n g s i t u a t i o n a r i s e s i n the 4p4f c o n f i g u r a t i o n o f As I I however. An extremely c a r e f u l u n s u c c e s s f u l search was made f o r the four l e v e l s s t i l l m i s s i n g i n 4p4f and 4p6p. On the other hand the terms J F y and Gs appear t o v i o l a t e the s e l e c t i o n r u l e on J since they combine o c c a s i o n a l l y w i t h J = 1 l e v e l s . I t seems more probable t h a t i n each case two l e v e l s are superposed than t h a t forbidden t r a n s i t i o n s are o c c u r r i n g ( e s p e c i a l l y f o r * G j ) . In the 3 case of Fy the coincidences may w e l l be a c c i d e n t a l . The bulk of the experimental a n a l y s i s has been c a r r i e d out i n As I I r e s u l t i n g i n a great extension and complete r e v i s i o n of the e n t i r e spectrum. Of the l i n e s f o r which a Zeeman e f f e c t i s quoted (6) only one remains u n c l a s s i f i e d , namely A 4619.52. A l l others have been f i t t e d i n t o 59 As I I w i t h but one exception. The l i n e }-4627.6o i s a I I I l i n e from i t s behaviour on the p l a t e s and forms part of the 5d - 5f m u l t i p l e t . The p a t t e r n quoted i s not i n c o n s i s t e n t w i t h the assignment. The i o n i z a t i o n p o t e n t i a l of As I I has been reduced by 10,700 cm.\"' from the p r e v i o u s l y l i s t e d value. P l o t s of (n* - n) aga i n s t T R have not been shown f o r any of the spectra since f o r unperturbed s e r i e s they are approximately p a r a l l e l to the T n a x i s . For perturbed s e r i e s too few members are known to make such a p l o t meaningful. A f a i r l y comprehensive t e s t of intermediate c o u p l i n g formulae and the extent to which they may be a p p l i e d has been made. A number of r e v i s i o n s of the formulae have occurred. When i n t e r c o n f i g u r a t i o n per-t u r b a t i o n s are n e g l i g i b l e the c a l c u l a t i o n s are s a t i s f a c t o r y , as e v i d -enced p a r t i c u l a r l y i n the c a l c u l a t i o n of g- f a c t o r s w i t h the \"best\" para-meters. Table XXII i s a summary of the values of the S l a t e r i n t e g r a l s obtained from a r s e n i c c o n f i g u r a t i o n s . R e g u l a r i t i e s among them, and w i t h those i n i s o e l e c t r o n i c s p e c t r a , are discussed e a r l i e r . Using the data now a v a i l a b l e i n a r s e n i c , the spectra of g a l l i u m , germanium, and selenium may be attempted w i t h greater ease. Table XXII; S l a t e r Parameters from Arse n i c C o n f i g u r a t i o n s (cm.'1) C o n f i g u r a t i o n i F G G' G G As I I ; 4s* 4p* 55,800 4P5p 8,064 1,891 1,542 4p5s 5,554 4p6s 1,982 4p7s 2,051 4S4? 1 As IV: 4p* 43,550 47,800 4s4p 50,657 4S5P 5,170 4s5s 4,646 4s6s 578 4s4d - 7 8 , 0 9 0(f) -7,8550) 4s5d 4s4f 5,500 6o Table XXII (continued) NOTE : Racah (27b)> has shown t h a t G^ must be p o s i t i v e f u n c t i o n s w h i le f o r 4snd of As IV we f i n d G\"* negative. This i s of course a d i r e c t r e -s u l t of the s i n g l e t s being deeper than the t r i p l e t s , and i s t h e o r e t i c a l l y unaccounted f o r . The anomalously l a r g e magnitude of G i n 4s4d i s due to the h i g h l y perturbed D, . Two f u r t h e r p o i n t s a r i s i n g from t h i s study worth emphasizing are the f o l l o w i n g . In the f i r s t place a s t a r t has been made i n cor-r e l a t i n g the terms of a c o n f i g u r a t i o n ( w i t h t h e i r L - S names) w i t h t h e i r proper l i m i t s . Secondly, the approach used here i n examining a r s e n i c would appear to be very rewarding, i . e . i n photographing and an a l y z i n g many spark spectra a t one and the same time. The r e l a t i o n s of Bacher and Goudsmit are i n f a c t based on such a sequence and repre-sent a powerful t o o l f o r t h i s procedure. These methods have been some-what extended i n the present t h e s i s . 6t Table VIIi L i s t of Classified Lines i n As I Vs : intensity on vacuum grating Pa t intensity on E - 1 (prism) Pw t intensity on constant deviation (prism) Q i intensity observed by Queney G0 , Grf i intensity on 21 foot grating * i the corresponding line i s doubly classified Notei Intensities are on a visual scale of 0 - 100. A l l lines intensity 0 are not measured with the microscope (giving reduced accuracy). Lines intensity 100 may actually be stronger i n many cases. Intensity Wavelength (air) Wave Number (vac.) P\u00E2\u0080\u009E Q Go A -( cm 5 9500.66 10749.02 5 9267.28 10787.70 I0d 8995.0 11116.71 15d 8924.8 11189.08 20 5 * 8869.70 11271.25 20 25 8821.72 11332.40 5 20d 8654.01 11552.17 5 5 8564.69 11672.64 5 5 8541.54 11704.28 3 20 8428.89 11860.71 3 1 8305.65 12056.69 2 8042.95 12429.83 5 5 79&>.22 12559.01 0 7863.43 12713.61 lOd 7410.0 15491.57 1 7384.6 15557.97' 2 0 6338.94 15771.16 5 1 0 5451.52 18529.09 5 5408.13 18485.56 l 5565.54 18359.25 Table V I I (continued) I n t e n s i t y Wavelength ( a i r ) V P Q G<, Gj o A 10 5 5196.10 2 2 0 5141.63 2 0 5150.78 3 5121.54 1 5083.76 3 83 5068.95 1 5 5043.50 65 50 10 55 5H9.58 55 50 0 25 5075.51 75 85 2 55 5052.85 50 60 0 50 2990.99 100 90 20 90 2898.70 100 100 55 loo 2860.44 75 100 4o 100 2780.22 6o 90 55 loo 2744.985 75 100 1 80 2492.95 100 100 100 2456.55 70 90 4 100 2437.23 90 100 5 100 2381.18 65 60 5 75 2570.76 65 6o 5 50 2369.65 40 50 2 20 2363.03 80 100 6 75 2349.84 60 80 5 50 2344.02 70 80 6 25 2288.10 65 4o 4 4o 2271.35 50 lo 5 2266.68 66 20 5 50 2228.65 50 2 0 5 2205.96. 15 1 2205.17 25 Id 3 2182.95 5 1 2176.26 25 lo 2 25 2165.51 50 2 4 10 2144.05 20 0 2 2135.80 65 4 2112.99 2 0 2089.70 25 2085.25 2 2079.81 0 2069.95 Wave Number (vac.) -1 cm 19259.86 19443.68 19484.80 19520.72 19665.02 19722.46 19822.78 32046.4 32507.6 32962.7 53424.0 34488.1 34949.4 35957.7 36419.2 40101.3 40695.5 41017.7 41985.2 42167.6: 42187.4 42305.6 42545.1 42648.6 45690.9 44015.1 44105.5 44856.2 45317.6: 45555.8 \u00E2\u0080\u00A2 45795.6 45955.9 46164.0 46625.9 46849.9 47511.2 47838.5 47940.6 48065.9 48295.3 (3 Table V I I (Continued) I n t e n s i t y Wavelength ( a i r ) WaveNumber (M A -t cm 0 2065.59 48596.7 10 2047.57 48822.6 20 2 2015.54 49652.6 10 2010.07 49755.5 20 , 2009.50 49752.4 4o .4 2005.54 49900.4 20 2002.55 49920.1 20 2 We) 1995.44 5 0 H 4 . 2 10 1994.86 50128.8 25 4 1991.10 50225.5 2 5 4 1990.57 50241.9 20 5 1972.65 50694. 10 0 1958.84 5 1 0 5 0 . 6 55 5 1957.58 51610.8 2 0 1917.22 52158.9 0 I90I.69 52584.8 50 5 1890.44 52897.7 2 5 2 1881.98 55155.5 10 2 1875.09 55587.7 10 1 1871.72 55426.8 50 5 1860.44 55750.7 50 4 1850.27 54o46.2 2 2 1847.55 54152.2 20 4 1844.46 54216.4 2 5 4 1851.55 54605.1 1 1816.81 55041.5 15 4 1806.15 55566.4 0 0 1798.95 55588.0 10 2 1791.80 55809.8 10 4 1789.88 55869.7 5 1789.18 5589L5 5 2 1781.55 5615L5 5 5 1758.61 56865.1 2 1741.28 57429.0 2 4 1759.49 57488.1 10 2 1752.86 57708.1 2 .44 57722.1 2 2 1729.79 57810.5 1 0 1712.52 58400.5 2 5 1701.20 58782.0 Table VII (Continued) Intensity Wavelength (air) Wave Number (vac.) V P 3 \u00C2\u00B0 A cm 0 1 1671.92 59811.5 10 5 1595.63 62749.8 0 0 1587.97 62973.5 0 1575.87 63457.0 2 4 1574.72 63503.4 2 2 1563.00 63979.5 0 2 1559.50 64123.1 1 1554.10 64345.9 1 0 1542.97 64810.1 1 1515.51 65995-1 1 1506.93 66560.I 1 1504.25 66478.5 0 1472.36 67918.2 0 0 1461.91 68405.7 Od 0 1422.86 70281.0 1 1412.90 70776.4 Table VIII\u00C2\u00BB L i s t of Classified Lines i n As II V? t intensity on vacuum grating P0 t intensity on E - 1 (prism) t intensity on constant deviation (prism) Q t intensity observed by Queney G0 , . intensity on 21 foot grating * i the corresponding line is doubly classified Notes Intensities are on a visual scale of 0 - 100. A l l lines intensity 0 are not measured with the microscope (giving reduced accuracy). Lines intensity 100 may actually be stronger i n many cases. Intensity Wavelength (air) , 5P *>i -hPi3?z -5P'P, -5p'DT -5s *P, -5P*P( -5 ? ^ -*P!$ -Pz -4 P \" V \ -4 P 3 % -5P'P,- -5sJP, -5P3S, -5s'P, -4 p , 3P 0 -4PJ/P, -5s JP. 5PJS, 5P'P, 4 P ; ;DZ -5s 'P; 5PJA 5P5D, 5S'P, V P * 4 P J 3P, 5s *P, 5P'S, 5sJP, 4 P J % 5s *Z 5PJDJ 5P'P, 5s 'P 5P'D2 5P'P, 5s % \u00E2\u0080\u00A2 5PJPZ 6eJP0 6s 'P, 5PJP. 6s 3P, 5pJDa. - 5P3P* \u00E2\u0080\u00A2 5p% 5PJP - 5pJDI 4d 'D2 5P'P, 6s'PZ 5P'P, 5PJS, 5PJS, 5P 'P, 6s'P, 6s *Pt 5PJPX 5P'D2 - 5PJPA - 6s3P\u00E2\u0080\u009E - 6s 3P, - 5PJP< - 5P % - 5P -'D* - 5PJD, - 4 P J 'P, 5PJB* - 5PJS, 5P'D, 6b% 6sJPt 5 p i s / 6s 'P, 5P JP, /7 Table V I I I (continued) I n t e n s i t y Wavelength Wave Number Term Combination ( a i r ) (vac.) Go G\u00E2\u0080\u009E o A cm 75 50 5 5252.3 19024.00 4d'F, _ 4f 'F, 12 10 5238.66 19085.55 4d /F J - 4 f /Fj 100 100 100 100 5251.40 19110.04 5s 'P - 5P % 60 60 10 25 5222.10 l9 l4o.4o 4d'EJ - 4f\"?GY 5 5218.55 19157.09 4d,P1 - 6p3D, 60 50 10 15 5215.40 19168.66 5P'P( 6b3?0 10 50 10 15 5205.28 19205.92 4dJP, - 4f'F i 80 80 50 65 5-182.10 19291.84 4p> 'D, - 5P'D2 80 75 45 50 5161.01 19570.67 5P'P, - 6s JP, 20 4o 5 5 5124.92 19507.08 5 ? ^ - 6s 'P, 100 200 100 100 5107.54 19575.46 5s 'P, _ 5p'DA 100 100 100 100 5105.57 19581.01 5s P2 - 5P3S, 50 4o 5 2 5078.76 19684.58 5PJS, - 5d^D, 5 20 l 5072.02 19710.49 5PJP, - 5d 3F z 1 6 5o4o.6o 19835.39 5PJP, - V 'P, 100 100 100 100 4985.46 20052.75 5s JP, _ 5P'P, 1 4964.85 20135.99 4d'p, - 4f 'F, 25 50 5 0 4921.86 20270.68 5P;D< - 6s ^ 15 55 10 10 4915.27 20339.10 5P'D3 - 5d ?F, 90 100 100 100 * 4888.56 20450.23 5s Po - 5P'P, 25 60 15 25 4845.88 20650.34 5P'D2 _ 6s'P, 50 50 15 4o 4811.80 20776.46 5PJPO - V 'P, 55 80 20 4o 4802.12 20818.33 5 P > - 5d'R 65 80 25 50 4799.40 20830.15 5P D, - 6s 'P, 80 80 4o 80 4787.10 20883.65 5s*P2 - 5P'D* 45 5 0 4742.25 21080.72 4d3D3 3wd50d l Id 0 * 4755.44 21111.47 4d'p, - 6P'P, 5 4751.50 21129.95 4d D3 - 4f'F, 100 100 100 100 4750.72 21132.54 - 5P3P, 10 * 4725.91 21154.05 \u00E2\u0080\u00A2 5 P % 1 10 4720.2 21179.19 4d*D3 \u00E2\u0080\u0094 4f % 90 100 100 100 4707.62 21236.23 4d'D, -6o 90 6o 50 4672.52 21395.76 - 5d \ 15 4o 3d 0 0 4656.72 21468.35 \u00E2\u0080\u00A2 5P 'P, 10 4o 1 0 0 4655.07 21568.62 4d*P, - 6 P ^ 85 60 50 4622.55 21580.36 V 3D, - 5P 'P, 85 100 50 - 4622.48 21580.69 - 5P 'P, 85 100 50 50d 35 4629.85 21592.96 5P'P, - 5d3DR 40 45 20 3 8 4617.04 21652.85 4d'Fj -90 100 80 100 50 4602.44 21721.54 4d'F3 - 4fJF(, Table VIII (Continued) Intensity Wavelength Wave Number (air) (vac.) - a A cm 60 90 50 50 50 4590.72 21777.00 50 6o 50 20 20 4580.75 21824.49 60d 20d 1 1 4574.57 21855.88 1 4565.02 21899.60 4o 55 15 50 1 4560.10 21925.22 80 100 50 75 60 4552.16 21961.46 4o 6o 20 10 4549.88 21972.47 100 100 6o 100 75 4548.94 21977.00 100 100 6o 6o 80 4545.51 22005.26 100 100 60 90 90 4559.74 22021.54 50 50 25 20 20 4552.21 22058.08 50 50 20 5 5 4528.51 22076.15 5 50 Id 0 4525.74 22099.45 75 90 50 50 25 4515.85 22158.15 4o 100 5ow 25 15 4509.12 22171.08 50 100 55 50 4507.67 22178.21 100 100 50w 100 100 4494.24 22244.48 50 25d 6o 50 25 4475.46 22557.82 100 80d 80 70 4474.46 22342.82 20 60 2 10 2 4471.22 22559.01 15 2 1 1 4468.96 22370.51 100 100 50 100 80 4466.57 22585.50 6o 20d 50 25 15 4461.85 224o6.05 6o 50d 25 6o 4461.11 22409.65 6o 50d 40 55 4460.11 22414.70 90 ioo : LOO 100 100 4458.48 22422.89 50 50d 50 55 4456.67 22452.00 25 60 5 0,25 1 1 4447.55 22478.10 5 25 2 0 4440.55 22515.40 100 100 50 100 75 4451.57 22559.06 100 100 50 100 80 4427.15 22581.68 70 80 4o 50 45 4420.91 22615.45 70 70 75 50 50 * 4415.48 22651.50 50 50 75 4o 45 4412.16 22658.29 20 50 l 0 1 4408.83 22675.41 65 80 4o 50 50 44o4.55 22698.57 5 25 Od 4592.60 22759.19 100 100 6o 50 4571.25 22870.55 100 100 6o 50 4571.19 22870.66 100 100 6o 6o 4571.14 22870.92 5P'D, 4d'p, 4d'D, 5PJD, 4d'D, 5s *P, 4d*D. 5P'D, 5 P A 4d'D, 4d'p, 4d*D, 5P,'D, 5P'S, 4d 'F, 5P'P, 5P p, 4d'p, 4d'p, 5s JP. 4dJP, 4d 'F, 4d'D, 5P'S, Sp*, 5P'D, 5P >, 4d'F, 4d'p, 4d D, 5P>, 4d JP, 4d*P, 4d 'p, 4d 'P, 5d F, 4f /G 3 6 P 'p, V, 6V% 5P>, 4f F, 5d'F, 5d F\u00C2\u00BB 4f*F, 6p 'Dj 4 f JF X V, 'p. 6p'Dj 5d p, 5d'FV 6P D, 5P S, 4f 'D. 4f GV 6p'D, 5d P, 6s'p, 5d,F, 5d*P, 4f 'D, 6P;p. 4f F A 5d*DJ 4f D, 4f D, 6P'P, 5 P>, - 5 d D a 4d F, - ht*Dx 4 p \"D, - 5 P V 4p' D, - 5P D, Table VIII (continued) Intensity (air) (Vac) p^ a <*\u00C2\u00AB A -/ cm 20 4o 5 1 2 4266.90 22892.12 50 75 25 25 45 4259.65 22921.20 100 50 70 45 6o 4252.86 22966.97 100 100 70 100 100 4552.14 22970.77 100 100 50 100 loo 4526.64 25152.87 100 90 4o 60 50 4525.88 25120.89 100 90 50 80 50 * 4515.67 25164.88 70 75 50 25d 25 4501.96 25228.71 70 75 4o 45 45 4299.55 25252.92 70 75 50 25d 4o 4297.20 25264.44 6o 50 20 5\u00C2\u00AB 20w 4278.65 25565.21 5 25 4258.55 25476.70 60 65 15 20 20 4249.18 22527.55 100 100 50 100 90 4242.99 25561.68 70 100 50 60 \u00E2\u0080\u00A275 4228.25 25645.92 50 50d 50d 4225.52 25659.08 60 50 10 55 25 4221.04 25684.20 55 50 Id 5 20 4214.70 25719.82 45 6o 2d 50 25 4209.54 25748.89 80 75 75 80 4207.88 25758.26 55 45 2 15 4205.56 25772.50 100 100 100 100 4197.59 25817.64 100 100 60d 60 4190.09 25859.14 75 50 25 10 4160.45 24029.11 90 6o 50 50 4157.57 24046.91 0 l 0 4142.20 24l54.4o 20 20 4128.80 24154.80 20 25 0 4128.50 24215.07 40 4o 1 4125.52 24244.51 100 50 50 50 4119.67 24266.97 50 6o 15 5 4110.94 24518.. 50 4o 50 l 5 4107.18 24540.77 10 25 0 20 4089.8I 24444.14 85 100 45 55 4085.92 24479.59 100 200 100 100 4o82.4o 24488.51 1 15 4068.0 24575.19 80 90 60 50 4065.26 24591.15-80 90 50 50 4o62.67 24607.45 25 15 4057.71 24627.50 20 55 l 4022.15 24855.52 Wavelength Wave Number Term Combination 4d'pa - 4f *D, 4dJP, - 4f *DA 5P'P, - 5 d V , 5s P, - 5P S. V'D, - 5P D, 5P'P. - 5P'D, 4d P, - 6 P 'D, 5P'P\u00C2\u00BB - 5d'p, 4P J,\ - 5 P \ 5b'?, - 5P D2 4 P J *D, - 5 A 4d P, - 4f D, 5 ? ^ - 5d'D, 5p'P, - 5d'F, 5p'D, - 5d Ds 5P'D, - 5d,D, 5 P P, - 4 P\"P, 4d p, - 4f V 4d'D, - 4f G, 4d'P, - kf,Vl 4d*D, - 6p'Pj 4dJD, - 4 f*F v 5p*D, - 5d'D, 5P'D, - 5d'P, 5P'P, - 5d'p, 5 P 'P, - 5d 'F, 4d'D, - 6P'P, 5P'D, - 5d'p, 5 ? % - 5d'D, 4d D, - 6p 7D, 5P'P, - 5d'FP, 5P'P, - 5d'p. 5 P > - 5d p, 4d Dj - 4f G v 4 p \"D, - 5P'P. 4d7D, - 4f D z 4dJD, - kfJG, 5p'P, - 5 d > 4d D, - 6p P, 4d'D, - 4f'D, 7o Table VIII (continued) Intensity Wavelength Wave Number Term Combination (jd D, . 6pJp.; i y D, - 5P7D, V, D, - 5P D, 4d D, - 4f*GA 4d *D, - 6p 'D, 5P'D, - 5d 'P, V 'D* - 5p'P/ V, Da \" 5p'D, 4d D, - 4f 'D4 4 p ' > , - 5P/P, 5p P, - 5d'Da 4d'DZ - 4f D, 4d'D, - 4f'D, V JD, - 5P'P, 4 P ; - 5P/P. 5 P P, - 5d'D, 5P'D4 - 5d'P, 5P'S. - 7s P, 4d*D, - 4f *D, 5 P X - 7s Jp. 5P'D, - 5 d / , 5P/DA - 5d P, . V D* - 5P P, 4P/D, - 5PJP, 5S'P, - 5P s. 5PX - 5d D, 4P\"DA - %>% 5P/D. - 5d P. 4 P JD, - 5 P / s, V,P, - 5d P, 5P,P/ - 5d'P* 4p''D, - 5p \ 5P> - 5d,P\u00C2\u00BB-5P A - 4 P /s, 5 P P, - 5d P, 5p P* - 7s P, Jp 'p, - % \ (air) (vac.) p p Q G\u00E2\u0080\u009E o A cm 50 100 4o 20 4008.98 24956.97 100 6o 50 4006.22 24954.16 100 90 4o 25 4006.18 24954.40 100 4o 25 4006.12 24954.78 0 10 5987.0 25074.45 75 65 25 5982.24 25104.42 45 45 . 0 5 3967.60 25197.05 100 100 100 80 \u00E2\u0080\u00A2 3948.52 25518.80 85 6o 4o 25 3945.75 25556.71 1 20 Od 5953-3 25416.77 100 90 80 80 3931.05 25431.32 4o 75 T20 15 3929.15 25445.74 20 30 5 3896.07 25659.65 5 20 3890.50 25697.70 100 5842.64 26016.42 100 loo 80 3842.59 26016.76 60 5842.55 26017.17 20 70 20 20 5840.81 26028.82 :5o\" 4o 5 25 3828.44 26112.92 5 15 3826.12 26128.75 25 50 0 10 3824.12 26142.41 3d 8 3801.69 26296.65 50 4o l 12 3799.52 26515.05 30 50 0 3789.20 26385.53 100 100 100 100 5786.98 26598.80 80 6o 20w 40 3770.90 26511.36 70 50 15 55 5749.63 26661.75 0 8 3748.08 26672.77 90 70 50 70 3720.10 26873.38 90 80 50 80 3671.70 27227.62 4o 4o 0 40 3664.51 27281.07 60 50 15 60 5656.59 27340.12 60 45 2 15 3644.99 27427.13 80 55 5 25 5585.52 27897.59 90 8o 65 \">255X/57 28148.56 35 55 0 0 5548.85 28170.12 1 1 3535.25 28278.49 10 25 1 5523.85 28369.97 2 20 3516.58 28428.62 90 75 20 75 5512.95 28457.99 7/ Table VIII (continued) Intensity Wavelength Wave Number Term Combination 4p D, - 5P DA 4pJ /D, - 5P 'D, 5p D, - 6d'F, 5P D, - 6d*D, 5s*P, - 7s'P\u00E2\u0080\u009E 5PA - 5dP, 5P'P, - 7s'P, 5P D4 - 7s P, 5 P ' s / - V s, 5 P D, - 5d p, 5P'S, - 6d'p. 5PJP* - V/s, 5P'P. - 7s P, 5P'S, - 7s p, 5P'P, - 6 d Fj 5P,PT - 6 d % 5 P P, - 5 d P. 5 P P4 - 7s P. 5P'P/ - V/s, 5P'D, - 6dYD, 5P A - 6d ip l 5P,DZ - 7s P, 5P P< - 7s P, 5P D, - 7 s T \u00C2\u00BB , 5P - 6d 'D, hd3Ft - 6pJDa 5P V- 6d F, 4d F, - 4f F, 4d*F, - 4f F, V \ - 5P ' 8 p 5 P V _ 6 d V 4d F, - hf\ 5P'D4 - 6d'F, 5 P > , - 6d;D7 5P'P, - 6d'p # 5P!D, - 7s'P* 5 P P, - 4 P'/s / 4dT\u00C2\u00BB - 6p P, 4d'FT - 6p'D< 4d*F - 4f'F (air) (vac.) PE P* Q o A -t cm 50 50 2 5504.06 28550.19 l 10 5490.51 28642.59 2G 50 5476,82 28755.71 45 50 5440.82 29054.54 6o 55 0 1 5401.55 29591.9 10 8 5589.7 29492.7 50 25 5587.90 29508.4 55 50 5585.90 29525.8 l 5 5579.55 29581.3 6o 55 5 5566.80 29695.5 10 5289.10 50594.7 5d 15d 5287.55 50409.2 70 4o 20 * 5285.01 50451.1 10 10 5242.76 50829.I 4o 50 5256.85 50885.5 6o 50 1 5225.51 50995.8 10 0 5196.25 51277.6 20 4o 2 5196.04 51279.7 50 0 1 5174.94 51487.6 10 5172.28 51514.0 50 5170.70 51529.7 50 0 5 5166.18 51574.7 25 4o 5157.86 51657.9 5 5146.27 51774.5 50 5140.00 51857.9 1 25 5151.72 51922.1 10 5129.55 51946.5 65 70 20 50 5126.86 51971.7 4o 4o 2 5122.05 52021.0 25 5120.17 52o4o.5 2d 25 :\" 5118.45 52058.0 90 100 70 '6o 5116.52 52077.8 4o 60 lOw 5098.63 52265.0 10 5098.18 52267.7 'a 1 5094.57 52505.4 20 4o 5 5091.07 52541.9 8 5082.64 52451.4 1 5069.14 52575.0 2 4o 0 5062.54 52645.2 60 100 50 60 5057197 -52691.96-Intensity 15d 75 90 : ; 50 50 jo o 5 59 5 59 5 25 25 75 75 5 55 2 25 20 6o 5 20 2 50 20 55 5 45 70 100 25 6o 50 50 5 85 90 45 4o 1 25 50 45 l 25 25 10 25 15 90 70 20 25 100 90 4o 4o 2 55 4o 2 l 15 8 5 25 l 5 50 55 4o 55 7Z Table VIII (continued) Wavelength Wave Number Term Combination (air) (vac.) e A cm_/ 60 15 1 5055.75 5055.58 3048.26 5016.62 3010.56 52757.5 52741.1 52796.1 55140.0 55209.0 4dJF, 5PJ3, 5P P. - 7s P, - 4f \u00E2\u0080\u00A2 F, - 4f F 4 - 6 d > a - 6dJDy 0 0 55 1 Od 5010.05 5007.22 5005.85 2996.79 2979.28 55212.4 55245.7 55281.2 55559.5 55555.4 4d*F\u00C2\u00A5 5P'P, 4 d % 5P P, 5P Da - 4f - tefr - 7a P, - 4pJ 's, 50 25 15 2971.50 2969.92 * 2968.26 2965.78 296I.60 55645.5 55661.1 55679.9 55750.9 55755.7 Jp'fi 5P,P\u00C2\u00BB 4d F f 5P'D, - 6&'D, - 6d'p4 - 7s'P, - 6p/D, 50 20 10 50 2959.59 2945.27 2942.95 2940.65 2957.59 55778.6 55942.8 55969.6 55996.2 54051.6 4d F v 4d'F, 5P P\u00C2\u00AB 5PA-5P\ . i - 4f G,. - 4f'GV - 6d'D, - 1% - 6d'F, Id 1 25 0 2928.11 2 9 H . 8 6 2911.06 2906.55 2905.95 54141.8 54552.5 54541.7 54595.0 54425.8 5P'D, 5P'D, 5P'D, 5p'PT 5P % - 6d*D4 - 6dJD, - 6&\ - 6 d V , - 7s'P4 75 5 80 2894.92 2891.80 2890.14 2887.17 2884.41 54555.2 54570.4 54590.5 54625.9 54659.0 5P'D, 5P,'D, 4d F, 5P'D, - 6&f, - 7s,P, - 4f Fy 10 15 2880.56 2879.04 2877.56 2872.40 2866.50 54707.7 54725.6 54741.5 54805.9 54875.5 5PJ>, 5P,D, 5P P, 4d'Fz - 6d'D, - 6d'p, - 6d'pz - 7s - 6P'p; 10 20 2856.00 2855.70 2852.18 2847.86 2847.45 55005.7 55052.0 55050.6 55105.8 55108.9 5P'D, 5PJ>, 5P*P, 4d>, 4d F, - 7s P, - 6d 'D, - 6d FDI - 6p U - 6P'D, 13 Table VIII (Continued) Intensity Wavelength Wave Numbe: (air) (vac.) Pv Q 0 o GW A -/ cm 85 80 25 80- 2831.17 35510.7 80 80 20 80 2830.37 55250.7 25 65 50 2828.81 55540.2 l w d l 5 2819.50 55456.9 25 30 1 2800.55 55697.0 6o 50 30 2790.57 35824.4 25 30 3 2790.19 35829.5 50 25 1 2782.64 35926.5 2d 2775.80 36o4l.o 35 40 2 2767.96 56117.0 5 2767.18 36127.2 5 2766.43 56137.0 3 2765.05 36155.0 1 10 2760.83 36210.5 2 20 * 2754.22 36297.2 25 1 2747.98 56579.6 50 90 l 50 2745.26 36415.7 6o 50 65 2741.57 36464.7 5 15 2757.49 36519.O l 8 2732.54 36587.9 10 2719.97 56754.2 15 20 * 2717.22 56791.4 15 20 2716.03 56807.5 50 40 8 2713.92 36836.1 55 50 15 2702.71 36989.0 4o 50 1 2701.35 37007.6 0 1 2695.52 57115.1 10 2688.15 57189.5 5 15 2679.05 57515.6 20 20 2662.99 37540.6 8 20 2610.00 58302.7 1 8 2605.34 38371.2 100 85 25 100 2602.00 38420.5 70 60 25 2598.67 38469.8 75 6o 25 2595.00 38524.1 20 2590.99 58585.8 5 20 2590.40 58592.5 10 20 2590.04 58597.9 4o 50 2576.15 58806.O 5 2569.92 58900.I Term Combination 4d - 4 f 'GJ 4 d F. - 4 f G\u00E2\u0080\u009E 5 P ;P! - 4PVS, 5p'D, - 6d F, 4 d F, - 4 f T) 4 4d \ - 6p 'D, hd\ - 6?% 5 P 'P, - 6d% 4 d V l - 4f'G V 5P % - 6 d 'D, 5P P* - 1* 4d*FJL - 4f'D, 5P 'h - 6d 'p. 5p P, - 7 s 'P, V'Pt - 6p'P, 4 d JF, - 4 f JD. 4 p ' 3R - 4 f 'F, 4 P ; yt - 4 f ; F , 4 P J 'p, - 4f'F< 5P % - 7s 'P, 4PJ/P\u00C2\u00BB \" 6P P, 5 P D, - 6 d D, 5P *D. - 6 d 'P, 4 P ' 'p, - 4 f F, 5P'D, - 6d'p, 5 P 'D, - 6 d D, 5 P JD, - 1, 5p D/ - 6d 'D, 5 p JDi - 6d'F, 4 P ' 'Dx - 6 P P, 4p 'D. - 6 p T , 4 p j ;D* - 4 f ' F ; 4 P J % - 4f'F, 4 P ' 'D, - 4 f'F, 5s'p, - 6 P'p, 5P'P, - 6 d JP, 4 P J 'P, - 6 p 'P, 5s 'P, - 4 f % 5P'P, - 6d'D i 7Y Table VIII (continued) Intensity Wavelength Wave Number Term Combination 4p P4 - 4f G, 5P*D, - 8s 'p V/P. - 6 P > , 5P,D* - 1, V - 6P'p, y > , - 6 P D, 4 P ' P, - 4f % 4P'/p, - 4f 'D, 5s PT - 6 P 'P, 5s X - 6 p 'D 4 5S'P, - 4f F, V/P, - 6 P/D, 5s P< - 4f F, 5 8 ^ - 4f YF, 4 P J 'p, - 4f JD, 4 P ' 'p, - 4f 'Dx 4P''pe - 4f }), 4 P ' 'p, - 4f'D. 4 P\"D Z - 6P'p, 5 P P, - 8s P. 5s 'P, - 6 P'p, 4 P ' 'D, - 4f'G, 4 P ' 'D, - 6P'P, 4 p ' > , - 4 f \ 5s B - 6 P'P 9 4 P 'pt - 6p'D, 4p' 'DT - 6 p 'D, (air) (vac.) Po Pv Q Go G\u00E2\u0080\u009E o A cm\"' 50 75 15 2561.09 59054.2 10 50 0 2559.58 59057.2 10 2558.87 59068.0 5 2545.45 59274.0 20 30 0 2559.50 59566.0 15 8 2529.16 39527.0 100 100 1 75 2527.54 59552.5 15 20 2526.25 59572.4 25 25 2508.04 59859.8 1 2505.94 59895.2 20 50 2501.54 59965.4 5 2498.45 40012.8 4o 50 25 2498.16 40017.4 1 12 2495.40 40061.7 5 2492.00 40116.5 50 60 5 25 2490.48 4oi4o.8 20 25 2478.82 40529.6 50 50 4 50 2464.72 4o56o.5 50 50 4 20 2465.98 40572.5 5 2462.08 4o6o5.8 90 50 6 - 50 2461.67 4o6lo.5 50 2 2459.74 4o642.4 10 2445.17 40884.6 70 85 4 50 2455.96 41059.1 10 50 2454.54 4lo65.o 5 2451.80 41109.5 1 1 2427.41 41185.6 70 50 6 0 2405.85 41552.7 10 2405.65 41556.5 l 2595.55 41770.0 20 4o 0 1 2589.68 41855.8 0 2 .1 '2574.17 42107.1 5 20 * 2572.00 42145.6 5 5 2556.29 42426.6 15 0 2235.27 44725.4 5 0 2221.00 45010.7 5 2116.76 47227.0 l 2114.58 47275.7 75 1 4 2109.77 47585.5 15 2102.80 47540.4 5s 'P, - 6 P DX V, - 4f'D, 5s P, - 4f D, 5s 'P, - 4f 'D, 4 P 'D, - 4p' RS, 5 8 ^ , - 4f JG, 4 P ; % - 6 p ^ 4 P % - h f f j 4p' % - 4f \ V - 6 P ' P / y 7f Table VIII (continued) Intensity Wavelength Wave Number Term Combination . 3 3 i 4p, ,D. - 4f F, (air) * (vac.) Po Pw Q % % o A cm\"' 0 2097.57 47659.0 5o o 4 2095.42 47708.0 5 2094.79 47722.2 10 2095.06 47761.7 6o 4 2088.13 47874.4 3 2000.74 49965.2 (vac.) 25 l I988.96 50277.5 50 l 1983.65 50412.1 5 1968.72 50794.4 5 0 1964.52 50903.0 1 1947.57 51246.0 5 2 1943.29 51459.1 50 5 1912.96 52275.0 50 5 1860.44 55750.7 50 4 1769.04 56527.8 65 6 1660.67 60216.7 55 1612.09 62021.2 35 1571.00 62652-7 5 2 1568.22 65166.6 4o 4 1558.83 64150.7 70 6 l ' ' C . -;}1448.60 69052.2 20 l4o4.20 71214.9 6o 4 1400.42 71407.1 6o 1394.74 71698.0 55 5 1375.14 72719.9 50 4 1373.68 72797.2 6o 5 1369.85 75000.7 6o 2 1356.04 72744.1 50 2 1541.56 74540.1 25 2 1307.82 76462.1 25 5 1505.72 76586.1 45 4 1287.56 77666.2 45 4 1281.00 78064.0 25 4 1267.63 78887.4 30 5 1266.4o 78964.0 4o 5 1262.81 79125.8 50 4 1258.65 79450.2 50 1250.10 79993.6 20 1245.70 80276.1 4o 5 1243.17 80459.5 4 P S \ - hf'?, 4P* 'D, - 6p'D4 4p* \ - 4f F A 4p' SB, - 4f ,F i 4p \u00E2\u0080\u00A2 D, - hf Fv 4p* *Di - 4f i G i y - 6P;D,-4p' *Dt - 6P 'D, 4p\"D, - 6p'D, 4p Dt - 4f D, 4p' 'D, - 4f JD, 4P* % - ko'% 4 P > - V/S4 4P'S, - 5s P, 4P's. - 5s'P. 4P's. - 4P ; P / 4 P P t - 4 P 'D, 4P 'D\u00E2\u0080\u009E - 4P; 4 P 'D4 - 4p' 'D, 4P'D, - 5s V h ? i \ - 4^'D, 4P P, - V,'D, 4 P \ - 5s P, 4 P P, - 4 P D, 4 P D, - 4P; D, 4P P. - 4P D, 4 P DZ - V/P, 4p'SP - 4d*D, 4P;P, - 5s > 4P'p, - 5s P. 4PJP, - 5s'P, 4P's. - 4d R h?sPx - 5B\ 4p'P. - 5s'p, 4 P p 4 - 4d'F, 4P's - 4d*P, 4P;p, - 5B R 4p'p, - 5 a \ 76 Table V I I I (continued) I n t e n s i t y Wavelength Wave Number Term Combination (vac.) (vac.) Q G 0 G v A cm-' 3 4 124l .4o 80554.2 4p PK - 4 P D, 2 1 2 2 3 . 2 2 81751.4 4 p j p , -5s'P/ 1218.21 82087.7 4p px - 4pJ JP, 20 1211.25. 8 2 5 5 9 . 3 4 p ' p A - 4 p J , P 4 1207.55 8 2 8 I 3 . 7 4 P PE - 5s *p, A. 3 2 1 1 9 6 . 5 7 8 3 5 7 2 . 2 4p R - 4p P, 0 1 1 8 9 . 9 5 8 4 0 3 7 . 1 4 P P, - V *Pt 2 1181.60 8 4 6 3 1 . 0 4p P\u00E2\u0080\u009E - 4p P, 1 1 5 9 . 0 5 8 6 2 7 7 . 6 4p'p, - 4 d V 2 1 1 4 9 . 4 5 86998.I 4p PZ - 4d Yj 0 1 1 3 9 . 5 2 8 7 7 7 1 . 7 VP, - 4d*FL 1124.10 88960.I 4p'DT - 4 d D, 1118.04 8 9 4 4 2 . 2 4P'D4 - 4d*D< 1 1107.54 9 0 2 9 0 . 2 4 p ' D l - 4 d % 0 1 0 9 4 . 2 0 9 1 5 9 1 . 0 4p'D2 - 4d'P, 1 0 8 5 . 8 2 9 2 0 9 6 . 5 4p's, - 6 s *P, 1 0 8 4 . 5 8 9 2 2 1 8 . 6 kp'Dt - 4dYP4 5 1 0 8 2 . 5 8 92589.O 4 ? ' ^ - 4d'p, 1081.10 9 2 4 9 8 . 4 4p'D4 - 4d'P, 1 0 5 1 . 0 0 9 5 1 4 7 . 5 4 P's e - 6s'P, 1057.18 9 6 4 1 5 . 5 4 P's. - 4 P ' P, 1 0 5 6 . 0 0 9 6 5 2 5 . 1 4 ? ^ - 4 d D, 1 0 5 0 . 9 0 9 7 0 0 2 . 6 4p P4 - 4d.'Di 2 1 0 2 2 . 0 5 9 7 8 4 4 . 5 4p P^ - 4d*D_, 0 1 0 2 0 . 4 4 91996.9 ^'P, - 4 d ,D / 2 1 0 1 5 . 4 7 9 8 4 7 6 . 6 4p'p, - k&\ 1 0 1 2 . 6 5 9 8 7 5 0 . 8 4 P's, - 5d',D, 1 0 1 0 . 7 4 9 8 9 5 7 . 4 4p*P, - 4d'p, 0 1 0 0 9 . 5 1 9 9 0 5 8 . 0 4p'p, - 4d*D, 2 1 0 0 2 . 5 4 9 9 7 6 6 . 5 4 P P^ - 4d'p. 1 0 0 0 . 6 6 9 9 9 5 4 . 0 4p p - 4d D 9 9 5 . 8 0 100421 4p P - 4d P 985.81 1 0 1 4 5 ^ ; 4 P ' P , - 4d ' P , . 984.91 7 101532 v ' 4 P>, - 4 d % Vr r-974.64 102602 4p'P4 - 4d'E 956.07 104594 4p'D, - 6B'P, 942.81 106065 . 4p'Se - 7s P, 929.04 I 0 7 6 3 8 4 P 'D, - 6s'P/ 9 1 9 . 2 3 1 0 8 7 8 6 . 4p'D4 - 5d ,F 1 918.15 108914 4p'D4 - 4p' 'p 77 Table VIII (continued) Intensity Wavelength Wave Number (vac.) (vac.) Q Go <*v A . cm\"' 917.41 109002 913.68 109448 903.50 110680 898.95 111240 891.50 112170 887.04 112754 884.05 115115 881.60 115450 879.48 115705 874.90 114298. 859.87 116297 858.35 116505 857.07 116676 854.83 116982 849.34 117758 848.73 117825 845.98 118206 840.16 119024 835.36 119708 * 831.26 120299 828.62 120682 * 824.14 121554 820.96 121808 818.67 122149 816.88 122417 809.72 125499 805.62 124128 802.90 124548 792.72 126147 780.54 128116 777.67 128589 759.57 151688 752.85 132832 741.24 154909 Term Combination 4 P ' p z 4 P D, Jp X 4 P p, -4d'D. 5d'F, 5d D\u00C2\u00AB 5d,D, 6s'p, %> 'p, 4P'P, 4p D4 V^i - 5d'D i 5d'P, 6s'P, '5d>a 5d F, . i 4p P, 4 P > 4p'p, -6 8 ^ 5d 'P, 6s 'P, 5d'F, 6s'P, 4PJP, 4 P P, 4p P. % 'P, -5d'F, 5d/p, v ; p 5dID_/ V,P. f p ^ VP, -5d>, 5d,D, 7s P, 5d'P, 5d ,P / 4 p 'P. 4p'D 4 VP, -5d'p, 6d px 6d 'F, 7S'P, V's, 4 p i p * 4p p, 4p'p, 4 P 'p , - 6d7F, 6d;D, 6d'p. 8s V 7* Table IXt Terms of the As I I Spectrum Term 1 J Level I n t e r v a l n* g > p 0 1 2 0.0 1059.4 2557.2 1059.4 1477 .8 1.7090 1.7151 1.7067 1 D 2 10090.8 's 0 22594.9 'P 1 95525.1 2.8261 0.812 'D 1 2 5 96909.7 97109.6 99195.6 199.9 2084.0 2.8677 2.8751 2.8502 O.895 1.174 1.525 '? 0 1 2 98252.8 99175.7 100255.6 942.9 1079-9 2.9o4o 2.8498 2.8787 1.589 I .455 }s 1 101084.4 2.9015 I .896 'D 2 102587.1 2.9585 1.046 s 0 105784.4 5.0418 p 1 121597.4 5.898 1 2 5 121466.9 124652.9 5186.0 5.905 5.919 1.27 7P 0 l 2 125997.4 125698.6 124158.6 -298.8 460.0 4.086 4.065 5.886 'D 2 124647 .8 5.919 1.00 F 121515.9 5.906 1.00 J F 2 4 121619.5 121564.9 124205.6 - 54.6 2658.7 5.915 5.909 5.889 O.85 1.10 1.17 h 5 4 5 124154.5 121621 124700.8 -2512.6 5079.1 5.884 5.915 5.925 0.98 1.09 1.21 Table IX (continued) Term J Level Interval n* g 4 P 4 f G 4 124865.0 3.954 1.07 3D 1 125205.0 5.958 0.498 . 2 125241.0 58.0 5.960 1.11 5 'D 2 124960.0 3.941 0.82 (?) 4p7p and 151800 4 P 5 f 15i867 151874 152555 152567 155265 155405 155792 155906 154276 154600 154707 154814 154833 r S 2 54812 3 D . 1 75744.4 2 75856.8 112.4 5 742>8.8 582.0 D 2 85095.2 0 84642.8 1 84650.4 - 12.4 2 85100.2 469.8 P 1 119009.2 3s 1 150664.9 1.6458 0.508 1.176 1.555 1.15 4 P5s P 0 78725.4 2.4767 1 79122.8 597.4 2.4856 1.424 2 81503.4 2580.6 2.4740 1.492 'p l 82815.7 2.4968 1.075 to Table IX (continued) Term J Level Interval n* g 4p4d 'F 2 88823:6 2.6725 0.85 3 89544.0 720.4 2.6882 1.12 4 90922.1 1378.1 2.6544 1.24 7D l 99060.2 2.9273 0.75 2 99543.4 483.2 2.9411 1.27 3 100385.7 842.3 2.8822 1.25 'P 1 101483.1 2.9127 1.00 F 3 102481.7 2.9411 1.09 o Jp 0 102544.9 2.9430 1 102589.7 44.8 2.9443 1.44 2 102309.9 -279.8 2.9362 I .453 'D 2 111526.3 5.2444 4p6s JP 0 114495.6 5.5020 1 114695.9 202.5 5.5120 1.4o 2 117580.0 2684.1 5.4995 1.49 'P. 1 117759.8 5.5172 1.11 4P5d 3F 2 118886.4 5.759 0.71 5 II9552.6 646.2 5.778 1.124 4 121438.1 1905.5 5.716 'D 1 121553.9 5.895 0.727 2 120768.6 -585.5 5.856 1.44 (?) 5 122857.4 2068.8 5.801 1.285 \u00E2\u0080\u00A2*P 0 125516.4 5.844 1 125494.1 -22.5 5.842 I .54 2 125222.7 -271.4 5.825 1.16 (?) 'D 2 125782.9 5.861 I.151 'F 5 124390.8 3.902 1.044 'p 1 126602.6 4.o6l 4P7s J? 0 128568.4 4.496 1 128684.1 115.7 4.508 2 131555.5 2851.4 4.498 YP 1 131915.2 4.538 Table IX (continued) Term J Level Interval n* 4p6d 2 5 130771.2(?).:. 131141.1 369.9 4.745 4.788 1 2 5 131442.0 131251.5 -190.5 133901.1 2649.6 4.827 4.790 0 1 151480.0 (?) J. 2 155917.1 4.768 'D 2 154225.2 4.807 7F 5 154650.5 \" 4.861 4p8s 0 155967.0 5.557 (4 P5g) i 5 156585.1 III ( JP) limit 150290 n Table XIV: L i s t of Classified Lines i n As III Vy : intensity on vacuum grating P0 : intensity on E - 1 (prism) : intensity on constant deviation (prism) Q : intensity observed by Queney Cr0 , Qt4 : intensity on 21 foot grating * : the corresponding line is doubly classified Note: Intensities are on a visual scale of 0 - 100. A l l lines intensity 0 are not measured with the microscope (giving reduced accuracy). Lines intensity 100 may actually be stronger i n many cases. Intensity Wavelength Wave Number Term Combination (air) (vac.) 5f JF - 6g^G 4d*D / 4- 5P>, 4dJ>,i- 5p;P,i 4 d ^ - g p f y 4 P A ^ - 5P P,i P* Q Go o A cm 15d 7259.7 15770.88 100 20 7259.55 15809.71 lob * 6925.9 14458.75 50 * 6880.0 14550.88 50 2d 5968.0 16751.40 JwdJOd Id 0 * 4755.44 21111.47 85 100 4o 85 55 4627.60 21605.44 5 50 0 0 * 4625.50 21614.19 75 100 50 70 25 4607.22 21699.OO 12 4498.52 22225.52 5 20 Od 4490.22 22264.40 1 12 0,5 4455.55 22559.82 6o 100 50h 6o 45 4226.82 25651.81 100 50h 50 55 4226.64 25652.82 100 100 90 4o 4101.59 24575.12 100 100 75 55 4101.25 24576.07 2 10 0 4088.15 24454.18 1 5 4079.90 24505.51 100 400 100 100 4057.05 24765.59 80 200 100 75 4052.41 24792.08 5f */ - 7g*G 5d/D,i- 5 f :% i 6p*P/4> - 6 i \ i 6p^P,i -6 P P^- 6d*D,4 %>,\S* \" 3 P ? i , s i \" 5P>4 4 P \" S F - 5P \ 4px/3x - 5 P/P,i 4 f*F,j- 6d4D,z 4 f ^ \u00C2\u00A3 - 6d V * 5s S 4 - 5PJP<| 4 f V x - 5g'c Table XIV (continued) Intensity- Wavelength Wave Number Term Combination 4 f F,4- 5 g o 5 f 2 F I I - 8 g;G 5 f 9 g G ( a i r ) (vac.) V P P vf \tf Q Go G V 0 A cm\"' 100 250 100 8 5 4 0 3 1 . 1 0 ' 24800.14 100 500 100 100 5 9 2 2 . 4 9 25486.81 2 10 3863.OI 2 5 8 7 9 . 3 7 2 15 5 8 6 1 . 4 5 25889.70 2 6 3 4 2 9 . 8 8 2 9 1 4 7 . 2 1 1 5 5 4 2 8 . 6 6 2 9 1 5 7 . 5 8 100 100 50 100 3 2 5 5 . 4 7 3 0 7 0 8 . 7 40 90 50 50 5 1 8 0 . 5 7 5 1 4 3 1 . 9 50 3175.48 3 1 4 8 2 . 2 50 1 5 1 7 4 . 4 5 3 1 4 9 2 . 6 55 90 5 50 2 9 8 9 . 4 2 3 3 4 4 1 . 6 80wl00 50 80 2981.84 3 3 5 2 6 . 6 100 100 45 90 2926.14 24164 .7 60 70 0 2 7 0 5 . 9 7 3 6 9 7 1 . 7 60 70 1 2 7 0 5 . 5 7 3 6 9 7 9 . 9 20 4 2 2 5 5 . 4 2 4 4 3 2 5 . 9 70 50 7 2 5 2 1 6 6 . 2 1 4614-9.1 80 50 6 10 2 1 5 6 . 1 5 4 6 5 6 4 . 8 1 2 1 5 5 . 7 9 4 6 5 7 2 . 1 6 0 50 6 5 2 1 5 1 . 4 5 4 6 4 6 5 . 6 70 60 6 25 2147.48 4 6 5 5 1 . 5 50 5 5 0 2 1 5 2 . 8 0 4 6 8 7 1 . 9 50 5 2 0 5 3 . 1 0 4 8 6 9 1 . 2 (vac.) 2 5 4 1 8 9 6 . 2 1 5 2 7 5 6 . 8 1 1 1 7 7 3 . 5 5 5 6 3 8 4 . 1 40 5 1 7 7 2 . 2 0 5 6 4 2 7 . 0 5 4 1 7 5 1 . 0 6 5 7 1 0 8 . 0 0 l 1 6 9 8 . 7 9 5 8 8 6 5 . 4 7 5 6 1 6 0 0 . 9 6 6 2 4 6 2 . 5 6 0 6 1 5 7 1 . 4 0 6 3 6 5 7 . 5 1 20 1564.84 6 5 9 0 4 . 3 60 5 1 5 3 0 . 6 0 6 5 3 3 3 . 9 60 5 1 5 2 8 . 9 2 6 5 4 0 5 . 6 0 1 5 1 3 . 7 9 6 6 0 5 9 . 4 10 1 5 0 2 . 0 5 6 6 5 7 5 . 7 50 5 1 2 7 4 . 3 0 7 8 4 7 4 . 5 50 4 1 2 6 9 . 0 0 7 8 8 0 2 . 2 10 0 1 2 3 4 . 0 0 8 1 0 3 7 . 5 20 4 1 2 2 9 . 1 3 813 5 8 . 4 50 5 1214 .08 8 2 5 6 6 . 9 5 f M -5P ;P/i -5 f \" 9 g > 6 s S-j 6 s 3 / 4 l0g*G 10g*G 5d*D / i 5 P ^ i -5d %i 6 g > 6 g G 5P P/i -P-i -5P 4 f 4 f V ' * -4 f \"V -4d D,i-4 d D,.-4p* \f 4 P *P,4-4p*/P4 7g'G 4 f 4 f *F, 4 f *F JL 5 p J / i 4 f 5 p ^ x - 6 d iD / i' 5P PA-y v 4 P P,i-K % \" 4 P P. -4 P ^ i -4 P ' %i -4 P *D,|-4p 2P,i -6 d D 4 i 6 d D,i \u00E2\u0080\u00A2 P \"s;, 4 ? v 4P' V i \u00E2\u0080\u00A2 5 P ^ i 4P I'* 4p* 4f 4 - 4 P J J S i 4d D,i 871.10 866.44 850.05 625.21 615.88 114797 115414 117640 159946 I62898 4 P \u00C2\u00A3 4 -4 P J , 4 -4 P ^ -4d*D, 4 \u00C2\u00A5>\u00E2\u0080\u00A2 4d V 6s *S J 6s*Sa 614.48 605.80 162759 165618 4pTj. -X. 5d*D 5 d - D 7 i Table XV: Terms of the As III Spectrum Term ODD: 4s* 4p 'p hs1 5p *P 4s\" 4f V 4 s l 5 f *F 4 P ' yS EVEN: 4s4p* *P 's *p 4s 5s S 4s 4d D 4s\" 6s *s 4s7 5d aD 4s 1 6d *D 4s* 5g 2G 4s*6g *G 4s z 7g J Level Interval n* 1 2 0.0 2958.0 2938.0 2.078 2.091 151452.7 152175.8 723.1 5.186 3.198 5* 164108.7 164100.7 - 8 . 0 5.909 5.909 2* 187516.5 187505.8 -10.5 4.884 4.885 1* 166662 i l i 2 | 654o4 66575 68271 1172 I696 2.022 2.027 2.054 1* 2* 85505.7 85624.3 320.6 I 2 107800.2 1 2 1* 113935 115417 1482 1 \u00E2\u0080\u00A2\u00C2\u00A7\" IO6689.O 2.845 1* 2* 117643.2 117736.2 93.0 2.982 2.985 i 2 162884.5 5.875 l i 2* I65617.3 165702.4 85.1 5.956 5.959 2* 188561 I88603 42 4.959 4.961 x l A3, 7jT>^ 2 188900.7 4.980 52>4g 201080.5 5-975 II 208428 6.975 u Table XV (continued) Term J Level Interval n* 4s*8g *G 3|,4| 212195.6 7.975 4sJ 9g AG \" 216462.5 8.975 4sX 10g*G \" 218798.5 9.975 IV ('s ) limit 228725 17 Table XVII: L i s t of Classified Lines i n As IV Vj s intensity on vacuum grating Pe t intensity on E - 1 (prism) Pj : intensity on constant deviation (prism) Q : intensity observed by Queney G0 , G,j : intensity on 21 foot grating * : the corresponding line i s doubly classified Note: Intensities are on a visual scale of 0 - 100. A l l lines intensity 0 are not measured with the microscope (giving reduced accuracy). Lines intensity 100 may actually be stronger i n many cases. Intensity Wavelength Wave Number Term Combination 5p J), - 6p*P, 5d D, - 6p'p, 5d D, - 6p*P, 5dJ>\u00C2\u00BB - 6 P J p t 5d'DT -5d D, - 6P'p, 5s s e - 5P P, 5s s. - 5P P, 5s '3, - 5P'P\u00E2\u0080\u009E 5s % - 5P P/ 58*8, - 5P'P, 5s's, - 5P> 5p P, - 5d DT V X - 5P/P, 5 P JP T - 5s D, *4i\u00C2\u00BBx - y, 4d p, - 5P P. 4dT, - 5p/P, 5p'P, - 5d'D4 4d p , - 5 P ^ 5p P/ - 5d \ (air) (vac.) Po P* Q % o A cm\"' 1 8d 4712.44 21214.51 2 12 4702.95 21257.52 8d 4692.57 21205.25 12 4687.50 21227.28 8d 4665.45 21428.18 2d 4655.57 21482.88 1 10\" 4524.2 22048.45 1 6o 4o6o.66 24619.60 35 100 2216.14 21084.2 50 100 5190.00 51558.9 55 100 0 0 2108.85 22157.0 65 80 10 2947.95 55912.0 1 60 2596.78 58497.7 5 2512.97 59781.6 Od 4 2482.07 4o26o.6 6 ivrs. f0 90 6 0 2461.20 4o6l6.6 1 80 6 2445.95 40871.6 2 2422.86 41074.5 25 100 6 0 2417.48 41552.8 5 2402.29 41597.0 Table XVII (continued) Intensity Wavelength Wave Numbei (air) (vac.) P. P* Q G0 G\u00E2\u0080\u009E A cm\"' 5 2398.18 41685.5 25 4 2508.10 45512.5 5 2305.82 45555.2 1 2 2300.73 45451.0 6 2300.01 45464.7 5 2266.08 44115.4 6 2263.07 44174.0 6 2255.09 44569.7 5 2145.70 46590.1 5 2142.52 46659.2 5 2155.S2 46805.6 4 2108.66 47408.4 4 2097.41 47662.6 (vac.) 60 7 1480.52 67545.8 l 1475.21 67879.0 2 1472.55 67909.4 1 1440.00 69444.4 4 1455.86 69644.7 1 1455.90 69759.9 5 1581.76 72571.5 2 1556.55 75728.4 2 1555.01 75800.2 5 1555.96 75857.4 5 1551.57 75999.0 5 1547.52 74210 .4 5 1542.69 74477.4 50 7 1299.52 76965.5 5 1079.47 92658.1 0 4 1005.60 99641.5 20 : 5 999^8> 100072 15 5 980.54 101984 10 5 971.20 102965 5 5 956.94 104500 6 955.51 104897 10 5 946.50 105652 10 0 941.98 106159 5 5 950.89 107424 50 6 892.68 112022 5 851.81 117597 0 2 762.08 151219 4d D, 4dJD, 5P'P. 4d*D, 5P'P* 5P'P, 5P P, 5P'P, 5P'P, 5P P, V , \ 5P'P, 5P P. - 5P Pa - 5P P/ - 5d D, - 5p P' - 5d D, - 5d Jp, - 5 d ^ - 5 d > - 6s S, - 6s ' S \u00E2\u0080\u009E - 5P/P, - 6s's, - 6s's, 4P'p, -4P' 'P, 4d 'D, - -5P % . v p, - 5P > - 5P'P. 4 P 'P - V P, 4p P, 4 P P, 4 P 4 'E 4d;D, 4d*D, 4d'D, 4d'D, 4 f F, 4 f Fj 4 f F v 4d D, - 5P P, . 4 s \" S. - 4p>P 4 P 'p, - 4P\u00C2\u00AB \ 4p 'P, - V 'a. 4p JP 2 - 4d'D, 4p R - 4pa )p, 4 P P, - W'P. 4p'p, - 4p 4 P \ - 4P* 'p. 4'K -4p<*p; 4 d D . - 4 f F , 4P'p, - 4P* 'p< 4p P - 53 S\u00E2\u0080\u009E 4 P \ - 4d YD Z ff Table XVII (continued) Intensity Wavelength WaveNumber Term Combination (vac.) (vac.) ft \u00C2\u00B0o Gw A cm\"' 4 760.80 131440 4pV, - 4dJD, 2 748.32 135632 4p'p, - 4dJD, 2 747.56 133768 4p'p, - 4d iD i 2 741.96 134778 4p'p\u00E2\u0080\u009E - 4dJD, 0 710.93 l4o66o 4pJPj - 5s S/ Table X V I I I : Terms o f the As IV Spectrum Term J Level I n t e r v a l n* EVEN: 4s* 'S 0 0.0 2.084 4p* 3 ? 0 179930 1 181465 1535 2 184289 2924 2.345 'D 2 204655 's 0 211679 4s4D 'D 2 179563 2.795 JD 1 210592 2 210725 133 5 210926 201 5.015 4s5s *S 1 220.22 3.087 'S 0 229414 3.168 4s5d 'D 2 292522 3.962 \" JD 1 295576 2 295634 58 5 295745 H I 4.020 4863 ^3 1 298869 4.080 's 0 300692O) 4.115 ODD: 4s4p P 0 75812 1 76965 1155 2 79480 2515 2.225 'p 1 112021 2.451 4s5p P 0 251207 1 251462 255 2 252280 818 5-298 'p 1 254055 5-418. ft Table MIII( continued) Term J Level Interval n* 4s4f J F 2 284452 5 284725 272 4 285158 415 2.837 F 3 285730(?) 3.847 4s6p 'p 0 316791 1 51688I 90 2 517059 178 4.484 As V (*Sj,) limit 4o4569 o 92 Table XIXs List of Classified Lines i n As V Vj J intensity on vacuum grating P0 : intensity on E - 1 (prism) P^, : intensity on constant deviation (prism) Q : intensity observed by Queney G0 , G* : intensity on 21 foot grating * : the corresponding line is doubly classified Notes Intensities are on a visual scale of 0 - 100. A l l lines intensity 0 are not measured with the microscope (giving reduced accuracy). Lines intensity 100 may actually be stronger in many cases. Intensity Wavelength Wave Number Term Combination 5s s^- 5P/. 5s s t - 5 P;p,i 5P D t i- 5 f / J t 5d D / t- 5f F T I 5p'P/^- 5(1*1), i 5P'P/1- 5 "Thesis/Dissertation"@en . "10.14288/1.0103748"@en . "eng"@en . "Physics"@en . "Vancouver : University of British Columbia Library"@en . "University of British Columbia"@en . "For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use."@en . "Graduate"@en . "A study of the spark spectra of arsenic"@en . "Text"@en . "http://hdl.handle.net/2429/40360"@en .