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UBC Theses and Dissertations

New spectra of some group V heteronuclear diatomics Hunt, James Edgar 1970

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NEW SPECTRA OF SOME GROUP V HETERONUCLEAR DIATOMICS by JAMES EDGAR HUNT B . S c , U n i v e r s i t y of Waterloo, 1967 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in the Department of CHEMISTRY We accept t h i s t h e s i s as conforming to the required standard. THE UNIVERSITY OF BRITISH COLUMBIA November, 1970 In presenting t h i s t h e s i s in p a r t i a l f u l f i l m e n t of the requirements f o r an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia, I agree that the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r reference and study. I f u r t h e r agree t h a t permission for e x t e n s i v e copying of t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the Head of my Department or by h i s r e p r e s e n t a t i v e s . I t i s understood that copying or p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l gain s h a l l not be allowed without my w r i t t e n p e rmission. Department of The U n i v e r s i t y of B r i t i s h Columbia Vancouver 8, Canada i i ABSTRACT Flash p h o t o l y s i s of AH^ (where A = P, As or Sb) 2 2 produces metastable A atoms in the D° and P° s t a t e s , AH, AH^ and A^. S i m i l a r t r a n s i e n t s were a l s o observed from A C l ^ with the exception of Sb^ from SbC1^• The reac t i o n forming A^ is probably: 2AH(2AC1) + A2 + H2(C12) Since t h i s r e a c t i o n i s endothermic f o r SbCl no Sb^ is observed f o l l o w i n g p h o t o l y s i s of SbCl^. From the p h o t o l y s i s of PC 1^ a new spectrum was observed 3 3 ~ and a t t r i b u t e d to PCI ( II Z ). The bands r e s u l t i n g from t h i s t r a n s i t i o n each c o n s i s t of three subbands which are e a s i l y recognized since the s p i n - o r b i t s p l i t t i n g i s less than the v i b r a t i o n a l spacings 3 3 -in the n s t a t e . The AG^^ value f o r the Z ground s t a t e i s s i g n i f i c a n t l y l arger than that reported by Basco and Yee^'^ from a long wavelength spectrum assigned to PCI. This system may a r i s e by absorption from the metastable 'A s t a t e which has the same e l e c t r o n i c c o n f i g u r a t i o n as the ground s t a t e . Spectra of the mixed Group V diatomics AsP, PSb and AsSb were obtained by f l a s h i n g corresponding mixtures of AH^ plus BH^-They are formed by: AH + BH -v AB + H„ i i i AsP was a l s o formed from the mixture of AsCl^ and PC 1^. That neither PSb nor AsSb were produced from the corresponding c h l o r i d e s is due to the probable endothermicity f o r the r e a c t i o n . The spectrum of AsP c o n s i s t s of a number of strong red o o degraded bands between 2030 A and 2260 A. Due to perturbations a v i b r a t i o n a l a n a l y s i s was not p o s s i b l e . A system of bands in the region of 3000 A to 3225 A a t t r i b u t e d to AsP by Yee and Jonesv ' was not detected. Two systems of red degraded bands are a t t r i b u t e d to PSb. o o System 1 (3^*70 A - 3690 A) has a l s o been observed by Yee, Jones (27) 0 0 and Kopp . System 2 (.2^20 A - 26^0 A) i s much stronger than system 1. Again, as f o r AsP, strong perturbations prevented a v i b r a t i o n a l a n a l y s i s . o A group of red degraded bands in the region of 3710 A o to 3525 A were a t t r i b u t e d to AsSb. This spectrum was a l s o observed f 28) by Yee and Jones . A v i b r a t i o n a l a n a l y s i s gave tog and <A>ex values of 2 7 ^ . 3 cm ^ and 1.1 cm ' f o r the upper s t a t e . i v TABLE OF CONTENTS Page T i t l e Page i Abstract i i Table of Contents iv L i s t of Figures vi L i s t of Tables vi i i Acknowledgements x Introduction 1 Experimental 6 Reaction Vessel 7 P h o t o l y t i c Flash Lamp 7 Spectroscopic Lamp 9 Spectrograph 10 Wavelength Measurements 11 Photography 12 F i l t e r s 13 Reagents 14 Mixtures 15 Results 17 Atomic Systems of P, As and Sb 17 Group VA Hydrides 18 V Page Group VA Chlorides . . . 18 Mixed Group VA Compounds 27 Discussion 38 PC 1 Spectrum • 38 AsP Spectrum 39 PSb Spectrum 40 AsSb Spectrum 41 Summa ry 42 Bibliography ^5 Appendix ^ v i LIST OF FIGURES Page 1. Schematic Diagram of Flash P h o t o l y s i s Apparatus 8 2. Absorption Spectrum of PC 1 [PC 1 ^ /Ar : 0.06/250 t o r r , 4.8 \is o o delay] (2200 A - 2500 A) 23 3. Absorption Spectrum of PCI [PC 1^/Ar:0.06/250 t o r r , 4.8 M S O O delay] (2000 A - 2200 A) 24 4. Absorption Spectrum of As^[AsH^/Ar:0.2/250 t o r r , 110 ps delay] 26 5. Absorption Spectrum of AsP[AsH^/PH^/Ar:0.1/0.05/125 t o r r , 1 10 us delay] 29 6. Absorption Spectrum of PSb System 1 [PH^/SbH^/Ar:2/0.4/250 t o r r , 4.8 M S delay] 31 7- Absorption Spectrum of PSb System 2 [PH^/SbH^/Ar:2/0.4/250 t o r r , 4.8 ys delay] 32 8. Absorption Spectrum of AsSb [Ash^/SbH^/Ar:1/1/250 t o r r , 5.2 M S delay] Ik 9. Absorption Spectrum of P atom [A. PH^/Ar:0.2/500 t o r r , 4.8 ys delay B. PhyAr:l/250 torr.no delay] 55 10. Emission Spectrum of P atom [A. PH /Ar:.0.2/50 t o r r B. PH3/Ar:0.02/5 t o r r ] 56 11. Absorption Spectrum of As atom [AsH^/Ar:1/250 t o r r , 4.8 M S delay] 57 v i i Page 12. Emission Spectrum of As atom [AsH^/Ar:0.2/50 t o r r ] . . . . 58 13. Absorption Spectrum of Sb atom [SbH^/Ar:0.4/250 t o r r , h.8 ys delay] 59 14. Emission Spectrum of Sb atom [SbH /Ar:2/250 t o r r ] . . . . 60 15. Absorption Spectrum of ?2 IPH^/Ar:1/250 t o r r , 110 ys delay] 62 16. Emission Spectrum of P [PH /Ar:1/250 t o r r ] 65 v i i i LIST OF TABLES Page 1. Summary of Low-Lying Atomic States of P, As and Sb . . . . 19 2. Band Heads of the PCI Spectrum, System 1 (? \) 20 3. Band Heads of the PCI Spectrum, System 2 (A II -<- X E ) . . 21 k. Unassigned Bands Observed with the PCI Spectrum 22 5. Band Heads of the As2 (A \^ «- X ' z * ) Spectrum 25 6. Band Heads of the AsP Spectrum 28 7. Band Heads of the PSb Spectrum 30 8. Band Heads of the AsSb Spectrum 33 9. Summary of Transient Molecular Species Observed from the Flash P h o t o l y s i s of Group VA Hydrides and Chlorides . . . 35, 36 10. Summary of A d d i t i o n a l Transient Molecular Species Observed from the Flash P h o t o l y s i s of Mixed Group VA Hydrides and Chlorides 37 11. L i s t of PI Atomic T r a n s i t i o n s Observed in Absorption and Emission 48 12. L i s t of Asl Atomic T r a n s i t i o n s Observed in Absorption and Emission 49, 50 13- L i s t of Sbl Atomic T r a n s i t i o n s Observed in Absorption and Emi ss ion 51 "54 14. Band Heads of the (C •*- X) Spectrum Observed in Absorption . . . . . 61 i x Page Band Heads of the P„ (c X) Spectrum Observed in Emission 63, ACKNOWLEDGEMENTS I am g r a t e f u l to Dr. N. Basco f o r h i s encouragement and guidance throughout t h i s work. I should a l s o l i k e to thank Dr. A.J. Merer for many h e l p f u l d i s c u s s i o n s . I wish to thank, in p a r t i c u l a r , my wife E l a i n e f o r typing and proof reading the manuscript and my parents f o r t h e i r support and encouragement. TO MY FATHER - 1 -INTRODUCTION The p h o t o l y s i s of phosphine has been studied by Melvi 1 l e ^3 3^3^ , and No r r i s h and 01 dershaw^3 5^ . M e l v i l l e measured the quantum y i e l d f o r the production of hydrogen under various c o n d i t i o n s . Using f l a s h p h o t o l y s i s and k i n e t i c spectroscopy Norrish and Oldershaw observed PH^, PH and but no phosphorus atoms. The p o s s i b l e primary p h o t o l y t i c steps are: PH^ + hv •> PH2 + H (1) PH3 + hv + PH + H2 (2) M e l v i l l e found that a d d i t i o n of atomic hydrogen during p h o t o l y s i s reduced the quantum y i e l d f o r decomposition of PH^. The i n t e r p r e t a t i o n is that heterogeneous recombination at the wal l s is enhanced by an increase in hydrogen atom c o n c e n t r a t i o n . PH2 + H + wal 1 -> PH3 (3) P o s s i b l e secondary reactions of PH2 are: 2PH2 P2 + 2H2 (k) PH2 + H -> PH + H2 (5) 2PH2 -*• PH + PH3 (6) Reaction (6) is f e l t to be predominent f o r the f o l l o w i n g reasons. Reaction (4) would be expected to have a much higher a c t i v a t i o n energy than rea c t i o n (6) and the absence of P^H^ in the r e a c t i o n - 2 -products favours ( 6 ) . If (5) predominated, a quantum y i e l d of unity would be expected and M e l v i l l e measured a quantum y i e l d of 0 .5 c o n s i s t e n t with rea c t i o n ( 6 ) . This implies that hydrogen a b s t r a c t i o n from PH^ occurs more r e a d i l y by PH^ than H. Formation of P^ is then given by: 2PH -> P2 + H2 (7) (35) N o r r i s h and Oldershaw found t h a t , in the absence of i n e r t gas, decomposition of PH^ increased by 80 to 100%. This was int e r p r e t e d as being due to a thermal e f f e c t . The p o s s i b i l i t y that the decreased decomposition on a d d i t i o n of i n e r t gas is due to t h i r d body recombination of the primary p h o t o l y t i c fragments is el i m i n a t e d by the observation that the e f f e c t s of a 12 f o l d and 200 f o l d a d d i t i o n of i n e r t gas are s i m i l a r . The p o s s i b i l i t y of thermal decomposition (43) is considered u n l i k e l y since Hinshelwood and Topley found no homogeneous decomposition of PH^ up to 770°C. If not due to thermal decomposition then the increased decomposition can be explained by: PH3 + H -> PH2 + H2 (8) Since the r a t i o of decomposition of PH^ in the absence of i n e r t gas to that in i t s presence changes very l i t t l e over a range of PH^ pressures of 0.1 to 10 t o r r , r e a c t i o n (8) is expected to have a small a c t i v a t i o n energy. The observation of the spectra of AsH2 and AsH ^ 7) (1 8) (1 5) . SbH2 and SbH( 3 6 ); NC1 £ and NCI ( 3 7 ) , PCI °6 ) , A s C l( 2 0 )' and SbC]{2k) - 3 " in the f l a s h p h o t o l y s i s of the appropriate hydride or h a l i d e suggests that s i m i l a r reactions occur f o r these systems. An extension of t h i s mechanism to e x p l a i n the production of atoms has been proposed by Basco and Yee . They could be produced by secondary p h o t o l y s i s : AH2(AX2) + hv -» A + H2(X2) (9) AH (AX) + hv -> A + H(X) (10) Other p o s s i b l e mechanisms are summarized by: AH + H(AH, AH2) + A + H2(AH2 > AH ) (11) AX + AX(AX2) -> A + AX2(AX3) (12) 2 Reaction (11) is s u f f i c i e n t l y exothermic to produce A( D°) atoms as well as ground s t a t e A. However, in order to account f o r e x c i t e d atoms from (12), AX or AX2 must be vibrationa11y or e l e c t r o n i c a l l y e x c i t e d . Such e x c i t a t i o n could r e s u l t from termolecular recombination or by primary or secondary p h o t o l y s i s . AX (AH) + X(H) + M -»• AX2"(AH2") + M (13) A + X(H) + M -> AX"(AH") + M (14) AX3(AH3) + hv -y AX2"(AH2"'C) + X(H) (15) AX2(AH2) + hv -»• AXW(AHK) + X(H) (16) Whichever mechanism is chosen f o r the formation of the atoms only one of the two e x c i t e d s t a t e s observed need be accounted f o r , since interconversion is p o s s i b l e by secondary absorption: A(V) c h vk . A(2P) <V h V ) A 2 P° (17) M,-hv hv - k -Evidence that t h i s does take place i s provided by observation of fluorescence from the s t a t e to both metastable s t a t e s ^ ' ~ ^ . Two a d d i t i o n a l p o s s i b i l i t i e s f o r the formation of using the atoms should be considered. 2A + M •+ A2 (18) A + AH (AX) A2 + H(X) ( 1 9 ) Reaction (18) is expected to be too slow to account f o r the rapid formation of A2 and reac t i o n (19) is considered unimportant since the formation of A2 is not accompanied by a corresponding drop in (15)(22) the ground s t a t e atom concentration . Thus the only important r e a c t i o n forming A2 i s : 2AH(AX) + A2 + H2(X2) (20) That Sb2 is produced from SbH^ while no Sb2 was observed from (15) SbCl^ is in accord with the probable endothermicity of reac t i o n (20) for SbCl. If r e a c t i o n (20) is the predominant rea c t i o n responsible for the formation of A2 then i t may be p o s s i b l e to produce the mixed diatomic AB from the system AH^AX^) plus BH (BX^) . The competing reactions are: 2AH(AX) -> A2 + H2(X2) (21) 2BH(BX) + B2 + H2(X2) (22) AH(AX) + BH(BX) + AB + H2(X2) (23) If we assume a bond strength f o r AB equal to an average of the bond strengths f o r A2 and B2 then r e a c t i o n (23) would be - 5 -exothermic except for SbCl. Then, provided the rates of reactions (21) and (22) are not much f a s t e r than r e a c t i o n (23) we may expect AB to be formed in a mixed system. By analogy with P^, r\s^, and Sb^ the corresponding mixed diatomics are l i k e l y to absorb in the u l t r a v i o l e t . For t h i s reason i t was decided to study mixed systems of P, As, and Sb hydrides and h a l i d e s since AsP, PSb, and AsSb had not p r e v i o u s l y been observed. While t h i s work was in progress these three molecules were reported by Yee and Jones in emission from flowing mixtures of the appropriate c h l o r i d e s through a microwave d i scharge (27) ( These spectra and others observed in t h i s work w i l l be discussed l a t e r . - 6 -EXPERIMENTAL The technique of f l a s h p h o t o l y s i s was f i r s t developed by Nor r i s h and P o r t e r ^ . Since then many instrumental improve-ments have been made. E x c e l l e n t a r t i c l e s on f l a s h p h o t o l y s i s and k i n e t i c spectroscopy have been published by N o r r i s h f ^ ^ , P o r t e r ^ , and No r r i s h and T h r u s h ^ . The basic features of the apparatus in t h i s i n v e s t i g a t i o n were those used by Basco and N o r r i s h ^ . A block diagram i s given in f i g u r e 1. A convenient lamp c o n f i g u r a t i o n with the reac t i o n vessel p a r a l l e l to the p h o t o l y s i s lamp was used. Both were encased in a brass c y l i n d e r l i n e d with an aluminum f o i l r e f l e c t o r . Light from a Lyman tube (used as the spectroscopic f l a s h ) was focused on the s l i t of the spectrograph by a sp h e r i c a l quartz l e n s . The p h o t o l y s i s lamp was operated from a D u b i l i e r 33-3uF, 10kV rapid discharge c a p a c i t o r which, when charged to 8kV, gave a discharge energy of about 1000 j o u l e s . The Lyman tube c a p a c i t o r ( D u b i l i e r 2yF, 10kV rapid discharge) was u s u a l l y operated at 9kV g i v i n g a discharge energy of about 80 j o u l e s . P h o t o l y t i c changes caused by the spectroscopic f l a s h were considered n e g l i g i b l e . The p h o t o l y s i s lamp was f i r e d by c l o s i n g a manually operated high voltage s w i t c h . The rapid r i s e in current through the p h o t o l y s i s - 7 -lamp ground lead induced a pulse in a c o i l around i t . This pulse was fed to the delay u n i t where i t was f i r s t a m p l i f i e d then delayed by means of a phanastron c i r c u i t . Various delays from 5 usee to 100 msec could be s e l e c t e d . The delayed pulse was then used to f i r e a thyratron which, on becoming conducting, allowed the c a p a c i t o r to discharge through the Lyman tube. Thus the absorption spectra of t r a n s i e n t species formed could be recorded at any desired time a f t e r i n i t i a t i o n of the r e a c t i o n by the p h o t o l y t i c f l a s h . Reaction Vessel The r e a c t i o n vessel (Suprasil q u a r t z , Englehard Industries Inc.) was 5 0 cm in length with an i n s i d e diameter of 1 cm and wall thickness of 0 . 1 cm. A side arm was connected to allow f i l l i n g and pumping. Plane windows (also S u p r a s i l quartz) were f i x e d to each end by means of an epoxy r e s i n . P h o t o l y t i c Flash Lamp The p h o t o l y t i c f l a s h lamp (Suprasil quartz) was 5 0 cm long with a 0 . 8 cm i n s i d e diameter and a wall thickness of 0 . 1 5 cm. The electrodes were made of tungsten and were s o f t soldered into a brass cone. The design employing a hollow e l e c t r o d e and manual c F i gure 1. Schematic Diagram of Flash P h o t o l y s i s Apparatus. A. E l e c t r o n i c delay u n i t ; B_. Lyman tube (quartz c a p i l l a r y ) with tungsten e l e c t r o d e s ; C_. Condenser (10 kV, 2 uF) ; D_. Condenser (10 kV, 33.3 uF); IE. Electromagnetic pick-up for s ignal to delay u n i t ; F_. High voltage switch (manually operated); G_. Condensing lens; H_. Hollow tungsten e l e c t r o d e ; J_. P h o t o l y s i s lamp (quartz) w i t h tungsten e l e c t r o d e s ; J_. Reaction vessel (qu a r t z ) ; K_. Brass casing l i n e d w ith aluminum f o i l f o r r e f l e c t i o n ; L_. Connection to vacuum system; M_. Spectrograph. - 9 -high voltage switch ( f i g u r e l) was used in the l a t t e r part of t h i s i n v e s t i g a t i o n . P r e v i o u s l y , in place of the hollow e l e c t r o d e , a side arm was connected to the lamp and no high voltage switch was used to i s o l a t e the ground e l e c t r o d e during charging. The pressure of argon (usua1ly about 60 t o r r ) was adjusted such that the lamp would not break down spontaneously on charging but would f i r e when a t e s l a c o i l was turned on near the side arm. Although t h i s arrangement was s a t i s f a c t o r y , the pressure in the lamp had to be adjusted f r e q u e n t l y . In a d d i t i o n , lamp breakage i n v a r i a b l y occured at the side arm. E l i m i n a t i o n of the side arm extended the lamp l i f e and the use of a high voltage switch made i t unnecessary to adjust the lamp pressure to the c r i t i c a l l e v e l . The photo-flash r i s e time and h a l f peak width were about 9 and ]h usee r e s p e c t i v e l y . Spectroscopic Lamp A Lyman tube provided the photographic f l a s h from which an absorption spectrum was recorded. A good continuous spectrum o o was obtained from 2000 A to 7000 A with a few s i l i c o n absorption and emission l i n e s . The discharge through the lamp was d i r e c t e d along a 5 cm length of quartz c a p i l l a r y tubing which was o p t i c a l l y aligned with the reac t i o n vessel and spectrograph. Light from - 10 -the Lyman tube was focused down the re a c t i o n vessel onto the s l i t of the spectrograph. A pressure of about 60 t o r r of argon was used. The h a l f peak width was about k ysec. Delay times were measured from the p h o t o l y t i c f l a s h peak to the Lyman tube d i s c h a r g e . Spectrograph Most of the work was done using a medium H i l g e r (model EJk2) prism instrument employing quartz o p t i c s . The spectrum obtained o o extends from 2000 A to 10,000 A and covered 22.1 cm, enabling i t to be recorded on a s i n g l e p l a t e . This made i t ideal f o r survey work. o o In a d d i t i o n , the good d i s p e r s i o n and speed from 2000 A to 2500 A made i t well s u i t e d f o r work in t h i s r e g i o n . o When accurate measurements were required above 2500 A a J a r r e l l Ash 3-4 meter Ebert mounting spectrograph was used. It had the f o l l o w i n g c h a r a c t e r i s t i c s : a) interchangeable plane g r a t i n g mounting b) two plane gratings each with 15,000 l i n e s o per i n c h , one blazed f o r 3300 A and the o other f o r 6000 A. c) one plane g r a t i n g with 30,000 l i n e s per o inch and blazed f o r 10,000 A. O d) r e c i p r o c a l l i n e a r d i s p e r s i o n of 5.1 A/mm 11 -in f i r s t order using the 15,000 l i n e s per inch g r a t i n g s . o e) 2500 A range covered by two 10 x k inch photographic plates using the 15,000 l i n e s per inch g r a t i n g in f i r s t o r d e r . Wavelength Measurements o Above 2200 A measurements were made using an iron arc as a reference. Below 2200 A, where there are few iron emission l i n e s , the iron arc was supplemented by a copper a r c . S i l i c a l i n e s and other known atomic l i n e s present in the spectrum under study were a l s o used. Iron standards were taken from p r i n t s (8) supplied by Adam H i l g e r Ltd . Standards f o r copper and s i l i c a (9) were taken from the Chemical Rubber Company Handbook The spectrum under i n v e s t i g a t i o n was f i r s t recorded then the reference was exposed by the use of a Hartmann diaphragm such that the reference overlapped an edge of the spectrum. The J a r r e l l Ash spectrograph was used p r i m a r i l y f o r o accurate measurements around 3600 A. The 30,000 l i n e s per inch g r a t i n g was used in t h i r d order g i v i n g a r e c i p r o c a l d i s p e r s i o n O _ j o of better than 0.7 A per mm or 8 cm per mm at 3600 A. The d i s p e r s i o n between the c l o s e s t reference l i n e s e nclosing the unknown was assumed to be l i n e a r . A measurement - 12 -accuracy of about ± 0.2 cm was a t t a i n e d . Conversion from wavelength in a i r to wavenumber in vacuum was done using a tab l e of wavenumbers published by the National Bureau of S t a n d a r d s ^ ^ . To f a c i l i t a t e measurements on the Medium H i l g e r , a o o c a l i b r a t i o n curve was drawn from 2084 A to 3906 A. Accurate measurements of wavelength versus p l a t e p o s i t i o n were obtained using a Grant l i n e measuring comparator (Grant Instruments I n c . ) . The c a l i b r a t e d region was di v i d e d into 26 sect i o n s and the c a l i b r a t i o n l i n e s w i t h i n each s e c t i o n were f i t t e d by the lea s t squares method to a cubic equation. These equations were then used to generate a table of wavelength in a i r and wavenumber in vacuum versus p l a t e p o s i t i o n . Conversion to vacuum was done using Edl^n's formula. The l i n e a r comparator was found s u i t a b l e only f o r sharp l i n e s p e c t r a . Most of the measurements were done using p r i n t s with the exception of high r e s o l u t i o n spectra which were measured d i r e c t l y from the plates using an eye p i e c e . Photography Photographic Plates o o In the region of 2200 A to 6600 A I 1 ford HP3 pl a t e s were used. They are f a s t panchromatic p l a t e s of medium g r a i n and contrast - 13 -and were supplied with a mauve a n t i - h a l a t i o n backing which cleared on development. The high speed is p a r t i c u l a r l y marked o for short times of exposure. Below 2200 A l l f o r d Q2 p l a t e s were used. They are intended f o r recording r a d i a t i o n normally absorbed by g e l a t i n emulsion. They have a very t h i n emulsion surface and are extremely pressure s e n s i t i v e . P r i n t Paper Agfa p r i n t paper was used f o r a l l p r i n t s . For most of the work BN2 ( a semi-matte medium hard) paper was used. When the p l a t e was of very low contrast an ex t r a hard paper, BEH2 was used. Deve1opmen t A l l photographic p l a t e s were developed in Kodak D19 developer f o r 5 minutes at about 20°C, with constant a g i t a t i o n . They were rinsed in a stop bath of 3% a c e t i c a c i d f o r 30 seconds, f i x e d in Kodak Rapid F i x e r f o r 2 minutes, and f i n a l l y washed for at least 30 minutes in water and d r i e d in a l i n t free d r y e r . P r i n t s were developed in Agfa Duotol f o r about 90 seconds at 20°C and then rinsed in a stop bath of 3% a c e t i c a c i d . They were f i x e d in Kodak Rapid F i x e r f o r at least 10 minutes and washed in running water f o r one hour. They were pressed and d r i e d in a p r i n t d rye r. - 14 -F i1 t e r s The p h o t o l y t i c f l a s h was used u n f i l t e r e d in a l l o o experiments. Measurements of AsSb between 3710 A and 3525 A were c a r r i e d out using the J a r r e l l Ash spectrograph in t h i r d o o order. F i r s t order i n t e r f e r e n c e (11,130 A to 10,575 A) was beyond the response of an HP3 photographic p l a t e . Second o o order i n t e r f e r e n c e (5565 A to 5288 A) was e l i m i n a t e d by using o o a Corning 7-54 f i l t e r and f o u r t h order (2782 A to 2644 A) was removed using a Corning 0-53 f i l t e r (standard p y r e x ) . A l l f i l t e r s were placed in f r o n t of the spectrograph s l i t thus f i l t e r i n g the scattered l i g h t from the p h o t o l y t i c f l a s h as well as the spectroscopic f l a s h . Reagents Argon Argon f o r mixtures, the Lyman tube, and p h o t o l y t i c lamp was obtained from Matheson ( i o n i z a t i o n grade - 99 - 999%)• It was taken from the c y l i n d e r and passed through a trap at ~78°C f i l l e d with glass wool. No a d d i t i o n a l p u r i f i c a t i o n was c a r r i e d out. Group VA Chlorides PCI and AsCl were obtained reagent grade from Baker - 15 -and Adamson Co. They were thoroughly degassed followed by trap to trap d i s t i l l a t i o n from room temperature to l i q u i d nitrogen over ^2^5 a n <^ A1C1 ^ (Baker and Adamson anhydrous). Only the middle f r a c t i o n Was retained f o r use. SbCl^ (May and Baker reagent grade) was degassed by pumping. As i t has a very low vapour pressure at room temperature no f u r t h e r p u r i f i c a t i o n was c a r r i e d out. Due to the high r e a c t i v i t y of PC 1^ and AsC l ^ s i l i c o n grease (Dow Corning Corporation) was used on a l l stopcocks, and once p u r i f i e d they were stored at l i q u i d nitrogen temperatures. Since SbCl^ has a very low vapour pressure and is q u i t e s o l u b l e in s i l i c o n grease i t was handled in a grease-free vacuum system f i t t e d with t e f l o n taps. Group VA Hydrides Phosphine was obtained from Matheson Co. It was thoroughly degassed and d i s t i l l e d from room temperature to l i q u i d n itrogen over P^O^. The top t h i r d was then removed by pumping and the remainder stored in a bulb at room temperature. S t i b i n e and a r s i n e were prepared by a method described by (13) Gunn et al . E s s e n t i a l l y , a r s e n i c ( M l ) oxide (Ma 1 1 i nckrodt Chemical Works) or potassium antimony t a r t r a t e (B.C.H. Laboratory Chemicals) was reduced by the a c t i o n of sodium borohydride (Metal Chemicals D i v i s i o n , Ventron Corporation) g i v i n g a r s i n e or s t i b i n e . These were then p u r i f i e d in the same manner as phosphine. Arsine was stored in a bulb at room temperature. S t i b i n e however, decomposes - 16 -slowly at room temperature and had to be stored at l i q u i d nitrogen temperatures. M i xtures A l l mixtures were made on a standard high vacuum rack. Pumping was c a r r i e d out using a s i n g l e stage rotary o i l pump in se r i e s with a two stage s i l i c o n o i l d i f f u s i o n pump. S i l i c o n grease was used on a l l taps. With t h i s arrangement a working vacuum of 10 ^ t o r r was obtained. Pressures greater than 5 t o r r were measured d i r e c t l y using a s p i r a l gauge. Mixtures r e q u i r i n g pressures less than 5 t o r r were made by expansion into c a l i b r a t e d volumes. A l l mixtures were d i l u t e d with argon to maintain isothermal c o n d i t i o n s during the f l a s h . To ensure homogeneity mixtures were made at least three hours before use. - 17 -RESULTS Atomic Systems of P, As, and Sb Metastable P, As and Sb atoms were observed f o l l o w i n g the f l a s h p h o t o l y s i s of PH^, PC 1^; AsH^, A s C l ^ and SbH^, SbCl^ using argon as an i n e r t gas (see tables 11,12,13 and f i g u r e s 9, 11, 13)- In a d d i t i o n , t r a n s i t i o n s from the ground s t a t e , ^°3/2' ° ^ ^ c o u^c' '3e s e e n- w a s n o t p o s s i b l e to observe t r a n s i t i o n s from the ground states of P or As since they l i e o below 2000 A. Fluorescence was a l s o detected f o r these atoms (see tables 11,12,13 and f i g u r e s 10,12,14). A l l P atomic t r a n s i t i o n s observed were between states of the same m u l t i p l i c i t y , w h i l e f o r the heavier As and Sb atoms, some t r a n s i t i o n s were observed between quartet and doublet s t a t e s . The s e l e c t i o n rules AL = 0, ±1 and AJ = 0, ±1 (J = 0 / J = 0) and the Laporte ru l e held f o r a l l observed t r a n s i t i o n s . The metastable P and As atoms decayed very r a p i d l y and were not observed beyond 20 ysec a f t e r the p h o t o - f l a s h . Excited Sb atoms were not observed beyond 75 usee, while the ground s t a t e lasted up to a m i l l i s e c a f t e r the p h o t o l y t i c f l a s h . The formation of Sb^ was not accompanied by a corresponding drop in the ground st a t e Sb concent r a t i o n ^ ' . - 18 -Group VA Hydrides Flash p h o t o l y s i s of AH^(A = P, As or Sb) with argon produced A^, AH, and AH^ as well as the corresponding atoms. From PH_ and argon the C ' z + X ' E+ system of P„ was 3 s u g 2 o o seen in absorption between 2030 A and 2160 A. In a d d i t i o n a number of emission bands from t h i s system were observed (see tables 14,15 and f i g u r e s 15,16). AsH^ and argon produced a spectrum due to the A +• X (19)(20) 0 system of As^ • Bands were observed down to 2050 A (see table 5 and f i g u r e 4 ) . (23) Two of the known systems f o r Sb^ were observed from SbH^ and argon. Group VA Chlorides PCI -3 When PC 1 ^  with argon was photolysed P C l ^ ^ , P^ and P atoms were produced. In a d d i t i o n a number of new bands were o o observed between 2000 A and 2500 A (see tables 2,3,4 and f i g u r e s 2,3)- None of these were observed from the mixture of PH^ and argon. AsCl., (21) P h o t o l y s i s of A s C l ^ produced As^, AsCl and As atoms, A number of bands between 2000 A and 2350 A t e n t a t i v e l y assigned by (22) C a l l e a r and Oldman as being due to AsCl were a l s o observed. - 19 -TABLE 1 Summary of Low-Ly ing Atomic States of P,As,and Sb State Leve 1 Atom Configuration Des i gnat ion J - 1 cm Kcal/mole 2 3 3S^ 3p^ 3p 3 V 3/2 0 0 11 3 P 3 2D° 3/2 1 1362 32.5 11 5/2 11377 32.5 P 1 11 3 p 3 2P° 1/2 18722 5k 11 11 3/2 18748 54 kS2 %>3 4 P 3 V 3/2 0 0 11 4 p 3 V 3/2 10593 30 1 1 5/2 10915 31 As 1 11 4 P 3 2P° 1/2 18186 52 11 1 1 3/2 18648 53 2 3 5S^ 5P* 5p 3 V 3/2 0 0 11 5P 3 V 3/2 8512 2k 11 1 1 5/2 9854 28 Sb 1 5 P 3 V 11 1/2 16396 47 1 1 1 1 3/2 18465 53 20 TABLE 2, Band Heads of the PCI Spectrum System 1 ( ? ] A ) Ass ignment v cm ^  (obs.) v cm ^ 0- 0 41334 41333 1- 0 42063 42065 2- 0 42741 42743 0-1 40766 40763 0- 2 40204 40200 1- 3 40372 40378 A G ] / 2 = 5 7 0 cm 1 -1 co =786 cm to x =27 cm e e " -1 * co =577 cm e to x =7/2 cm e e brational constants given by Basco and Yee. - 21 -TABLE 3.  Band Heads of the PCI Spectrum  System 2 (A 3n t- X Ass ignment v cm Ass ignment v cm 47049 47223 0- 0 46830 1-1 46992 46678 46830 47764 46507 1- 0 47548 0-1 46285 47391 46123 48482 45947 2- 0 48270 ' 0-2 45748 48107 45572 49192 3-0 48976 48809 T r i p l e t s p l i t t i n g is 379 cm (216 + 163). AGJ / 2=718 cm"1 " -1 AG. / 0=546 cm a - 22 -TABLE it. Unassigned Bands Observed with the PCI Spectrum Band Number v cm ' 1 40592 2 42209 3 42836 4 42925 5 ^3371 6 A3709 7 43867 8 43969 9 44219 10 44443 11 ^596 12 44858 13 45199 }k 45A07 Measurements less accurate ( ± 1 0 cm ) due to weak or diffuse band heads. Figure 2. Absorption Spectrum of PCI [PC 1./Ar:0.06/250 torr,4.8 ys delay] - 2k -i - 25 -TA BI E 5-Band Heads of the As,., (A +• X *E*) Spectrum Observed in Absorption 1 V 11 V cm 1(obs.) cm-'dit.)™ i V 11 V cm '(obs 5 3 40297 40299 18 0 44840 6 3 40565 40560 19 0 45078 5 2 40723 40721 20 0 45320 7 3 40800 40805 21 0 45557 6 2 40980 40982 22 0 45794 7 2 41228 41227 23 0 46025 8 2 41473 41471 24 0 46253 9 2 41724 41726 25 0 46477 9 1 42150 42151 26 0 46689 8 0 42324 42322 27 0 46917 10 1 42414 42413 28 0 46917 9 0 42574 42582 . '29 0 47312 11 1 42667 42670 So 0 47349 10 0 42837 42837 "31 0 47391 12 1 42926 42926 ''32 0 47599 1 1 0 43096 43095 "33 0 47799 13 1 43175 43177 '34 0 48020 12 0 43354 43350 *35 0 48233 14 1 43431 43428 13 0 43610 43604 14 0 43853 43854 15 0 44104 44103 16 0 44348 44352 17 0 44595 f44595 'A 1 my and (19) Ki nzer report bands up to (17>0) on 1 y Measurements inaccurate (±10 cm ) due to weakness of bands and diffuse appearence of band head. F i g u r e 4. A b s o r p t i o n Spectrum o f As [ A s H / A r : 0 . 2 / 2 5 0 t o r r , 1 1 0 ps d e l a y ] 2230 A 2113 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 - 27 -sbc 1 3 (25) SbCl and Sb atoms were observed f o l l o w i n g the ph o t o l y s i s of SbCl^. No Sb^ was detected however. Mixed Group VA Compounds When a mixture of PH^, AsH^ and argon was f l a s h o photolysed a new spectrum of red degraded bands from 2030 A to o 2260 A was observed which was not present when PH^ or AsH^ were used alone (see tab l e 6 and f i g u r e 5)- The same spectrum was present from the mixture of PC 1^, A s C l ^ and argon. A r e l a t i v e l y weak system of red degraded bands from o o 3^70 A to 3690 A and a strong system of red degraded bands from o o 2k2Q A to 2640 A were present when the mixture of PH^ SbH^ and argon was photolysed (see table 1 and f i g u r e s 6,7)- This spectrum was not observed from PH^ or SbH^ alone nor from the o o mixture of PC 1^ and SbCl^. The bands from 3470 A to 369O A (27) have been reported by Yee, Jones and Kopp who assigned the spectrum to PSb. Flash p h o t o l y s i s of the mixture of AsH^, SbH^ and argon o o produced a number of red degraded bands from 3710 A to 3525 A (see t a b l e 8 and f i g u r e 8 ) . This spectrum was not detected when AsH^ or SbH^ were photolysed alone or when the mixture of A s C l ^ and SbCl^ was used. Two of these bands have been reported by Yee (28) and Jones as due to AsSb. \ - 28 -TABLE 6.  Band Heads of the AsP Spectrum v cm v cm 1-49260 46188 49043 46134 48774 45850 48472 45823 48181 45586 47877 +45450 47825 45496 47550 45132 47488 44879 47170 +44790 46850 +44430 46551 44194 46518 Measurements less accurate ( ± 1 0 cm ) due to overlapping bands. Figure 5- Absorption Spectrum of AsP [AsH /PH /Ar:0.1/0.05/125 torr,110 ps delay] - 30 -TABLE 7. Band Heads of the PSb Spectrum  System 1 ('n «- ]Z+) Assignment v cm v cm (obs.) 0-2 27094.9 27093 0-1 27588.6 27585 0- 0 28085.2 28088 1- 0 28478.3 28480 2- 0 28874.7 28872 2-2 27884.9 27885 "System 2 -1 -1 -1 v cm v cm v cm 36843 38680 40842 36987 38888 40876 37092 3896I 41063 37209 38983 41310 37334 39178 41852 37590 39242 42017 37823 39457 42146 37902 39758 42214 38074 40020 42309 38132 40227 42468 38177 40304 42613 38316 40409 42791 38393 40560 42872 38643 40714 43251 Measurements are for the main heads of PSb as given by Yee and Jones Most of the bands in this system either overlap each other or appear diffuse. The resulting accuracy of band heads is ±10 cm Figure 7. Absorption Spectrum of PSb System 2 [PH /SbH./Ar:2/0.4/250 torr,4.8 ps delay] - 33 -TABLE 8. Band Heads of the AsSb Spectrum ,t Assignment • v cm -1 (28) v cm -1 AG v+1/2 A2G v+1 0-4 0-3 0-2 0-1 0- 0 1- 0 2- 0 3- 0 4- 0 1-1 '25944.2 26277-4 26615-9 26955-7 27297.1 '27160.4 26955.6 27296.9 27567.8 27835.3 ;28I01.4 '28370.7 27226.9 338.5 339.8 341 .4 270.9 267.5 266.1 269.3 1.3 1.6 3-4 to =27^.3 cm e u x =1.7 cm e e 1 1 - ] M i l _ j OJ =342.9 cm : to x =0.8 cm e e e Measurements are for the main heads of AsSb as given by Yee and Jones. Measurements uncertain due to weakness of the bands. - 35 -TABLE Q Summary of Transient Molecular Species  Observed From the Flash P h o t o l y s i s of Group VA Hydrides and Chlorides Transient Approx. P o s i t i o n E l e c t r o n i c o System Species of Bands (A) T r a n s i t i o n Reference PH2 (X 2B j ) 3850-5420 ^ 2A] -^ X 2B] SbHn/Ar 2 g g 39 PH3/Ar PH (X 3E ) 3300-3400 A 3n . + X V 31,40 P. (X 'E +) 2020-2860 C 1E+*-> X ]Z+ 41,15 2 g u g Asl«2 (X 23]) 3950-5025 A 2A] «- X 2B] 18 AsH^/Ar AsH (X V) 2900-3400 A 3n. X 3 E " 17 As. (X V) 2200-2450 A ' z+ ^  X V 31, 19 2 9 9 g SbH2 4600-5000 36 sbH (x V) 3300-3600 A 3n( <- X V 36 Sb„ (X 1z+) 2200-2300 F ^ X \+ 31 ,23 2800-3200 D +• X h+ 31,23 - 36 -TABLE q (Continued) Summary of Transient Molecular Species  Observed From the Flash P h o t o l y s i s of Group VA Hydrides and Chlorides Transient Approx. P o s i t i o n E l e c t r o n i c o System Species of Bands (A) T r a n s i t i o n Reference PCI (a 'A) 2300-2500 16 PCl./Ar (X V ) 2030-2200 A 3 n . -e X 3Z~ A s C l3 3 v g' J i p0 (x h+) 2030-2160 c h+ <- x ' z + 41,42 2 g u g AsCl 2400-2500 21,22 As„ (X 2200-2450 A 1 Z + «- X 1 Z + 31,19 2 g u g SbC 13 SbCl(X) 2260-2400 C +- X 25 - 37 -TABLE 10. Summary of A d d i t i o n a l Transient Molecular Species Observed  From the Flash P h o t o l y s i s of Mixed Group VA Hydrides and Chlorides Transient Approx. P o s i t i o n E l e c t r o n i c o System Species of Bands (A) T r a n s i t i o n Reference PH /AsH /Ar AsP (X 2040-2100 2090-2260 P C l3/ A s C l3/ A r AsP (X 2040-2100 2090-2260 PSb ( x h+) 3470-3690 ' n t - x ]i+ 27 PH /SbH /Ar 2420-2640 AsH./SbH./Ar AsSb (X 'z+) 3525"3710 28 3 3 - 38 -DISCUSSION PCI Spectrum When PC 1^  was f l a s h photolysed a number of v i o l e t o o degraded bands were observed between 2000 A and 2500 A. These were divided into two systems (see tables 2,3 and figures 2,3). o System 2, by far the strongest, extends from 2030 A 3 3 -to 2200 A. The bands have been assigned to a IT •«- X E 3 t r a n s i t i o n in which the t r i p l e t s p l i t t i n g in the II state is 379 cm '(216 cm ' + 163 cm ' ) . Bands resulting from such a t r a n s i t i o n are expected to consist of three.subbands as observed-The vi b r a t i o n a l structure of the band system was readily recog-nisable since the spacings between the subbands is smaller than the upper state vi b r a t i o n a l spacing of 715 cm '. The strongest progression was assumed to o r i g i n a t e from V" = 0 and due to the absence of bands in this progression below 46678 cm ' this was assigned as the (0-0) t r a n s i t i o n . Measurements were not s u f f i c i e n t l y accurate to permit a-deter-mination of co or w x values. The subband heads of the (2-0) e e e and (3-0) tr a n s i t i o n s appear d i f f u s e compared to the (0-0) and (1-0) t r a n s i t i o n s . This could be due to predissociation taking place. o o System 1 (from 2300 A to 2500 A) has been previously reported by Basco and Yee^'^. They assumed the lower state for - 39 -the observed transition was the ground state. However, the A G^2 °f 570 cm ' is s i g n i f i c a n t l y larger than the value of 5^ 7 cm 1 determined from system 2. System 1 and 2 must there-fore arise from different lower states whose to values are e similar. Rx, a „ a i m u 1 ( i t h <; (3D (32) (3D . P F(29) By analogy with S^ , 0^ , and PF the 3 -ground state of PCI is expected to be E . In addition these molecules a l l have low lying 'A states whose to values are close to that for their ground states. For this reason system 1 is thought to be due to absorption out of the metastable 'A 3 -rather than from the E state. Due to the rapid decay of PCI i t was not possible to establish that system 1 arises from a metastable state. In addition a number of v i o l e t degraded bands were observed between the two systems discussed. These bands could not be f i t t e d into either system 1 or system 2. Bands 3,6,9, and 11 (see table k and figure 2) appear to form an irregular progression with spacings of about 600 cm These bands could be due to a perturbed system of PCI or perhaps PC 1^ • A rotational analysis is needed to make an assignment here. AsP Spectrum Flash photolysis of the mixture of PH^, AsH^ and argon o produced a number of strong red degraded bands between 2030 A and - ko -o 2260 A (see table 6 and f i g u r e 5 ) . Since i t d i d not depend on the presence of hydrogen or c h l o r i n e (the same spectrum was produced from mixtures of PC 1^ and AsCl^) and required both phosphorus and a r s e n i c compounds, the spectrum was a t t r i b u t e d O o to AsP. The spectrum in the region of 3000 A to 3225 A (26) a t t r i b u t e d to AsP by Yee and Jones was not detected. The bands were assigned to a new s t r o n g l y perturbed system of AsP with an upper s t a t e frequency of about 330 cm Band spacings were very i r r e g u l a r preventing a v i b r a t i o n a l a n a l y s i s . At around 45450 cm ' and again at 47550 cm ' c l o s e l y spaced band heads are observed. These are l i k e l y due to v i b r a t i o n a l l e v e l s of perturbing e l e c t r o n i c s t a t e s . A r o t a t i o n a l a n a l y s i s is needed here. PSb Spectrum Two new systems of red degraded bands were observed when the mixture of PH^, SbH^ and argon were photolysed (see table 7 and f i g u r e s 6,7). This spectrum was not observed when PH^ or SbH^ were photolysed alone nor from the mixture of P C l ^ , o SbCl^ and argon. System 1 (the long wave 1ength. systern at 3470 A o to 3690 A) is in good agreement with a spectrum assigned.to PSb (27) 0 0 by Yee, Jones, and Kopp . System 2 (2420 A'-to 2640 A) is a t t r i b u t e d to PSb as well (see table 7 and f i g u r e 7). However, due to strong p e r t u r b a t i o n s , no a n a l y s i s was p o s s i b l e . Strong - 41 -bands around 39600 cm suggest a probable upper s t a t e frequency of about 270 cm \ Here a g a i n , as for" AsP, a r o t a t i o n a l a n a l y s i s is r e q u i r e d . AsSb Spectrum o A group of red degraded bands in the region of 3710 A o to 3525 A was observed when AsH^, SbH^ and argon were f l a s h photolysed (see tab l e 8 and f i g u r e 8). They were not detected from SbH^ or AsH^ alone with argon nor from the mixture of SbCl^, AsC l ^ and argon. Since the spectrum requires the presence of both AsH^ and SbH^ i t was assigned to AsSb. An upper s t a t e progression from the lowest v i b r a t i o n a l level of the ground sta t e was assigned. In a d d i t i o n two t r a n s i t i o n s from the f i r s t e x c i t e d v i b r a t i o n a l level of the ground s t a t e were i d e n t i f i e d . Measurements were s u f f i c i e n t l y accurate to determine to and e a) x for the upper s t a t e , e e The (0,0) and (0,1) t r a n s i t i o n s are in good agreement (28) with the assignment of AsSb by Yee and Jones . They report a weak band at 27160 cm ' as due to the (1,1) t r a n s i t i o n and were unable to observe any other e x c i t e d v i b r a t i o n a l l e v e l s in the upper e l e c t r o n i c s t a t e . The assignment here of the (1,1) t r a n s i t i o n to the r e l a t i v e l y strong band at 27226.9 cm ' i s consis t e n t with the rest of the a n a l y s i s . It is p o s s i b l e that the weak band observed by Yee and Jones at 27160 cm ' may in fact be the (2,2) t r a n s i t i o n which should l i e at 27154.5 cm \ - kl -SUMMARY The important reactions which are l i k e l y to take place when AH (AX ) are f l a s h photolysed are summarized below: AH CAX ) ^ AH2(AX2) + H(X) ( l ) 2 A H2( A X2) AH3(AX3) + AH(AX) ( 2 ) 2 A H ( A X ) -> A2 + H2(X2) (3) AH2(AX2) ^ > AH (AX) + H (X) (k) AH2(AX2) ^ A + H2(X2) (5) AH(AX) H(X) (6) AH + H (AH, AH2) —> A + H2(AH2, AH3) (7) AX + AX(AX2) A + AX2(AX3) (8) In order to produce metastable atoms by re a c t i o n (8) AX or AX2 must be vibrationa11y or e l e c t r o n i c a l l y e x c i t e d . Such e x c i t a t i o n may be produced by e i t h e r d i r e c t p h o t o l y s i s or a termolecular recombination. AH (AX) + H(X) + M -> AH "(AX ") + M (9) A + H(X) + M —y AH>:(AX") + M (10) AH3(AX3) ^ AH2*(AX2*) + H(X) ( l l ) - 43 -AH2(AX2) ArT(AX*) + H(X) (12) The main reac t i o n forming the mixed diatomic AB i s l i k e l y : AH (AX) + BH(BX) -y AB + H2(X2) (13) That PSb, AsSb and Sb2 were formed from the corresponding hydrides but not from the h a l i d e s is due to the probable endothermicity of reactions (3) and (13)-A system of strong red degraded bands in the region of o o 2030 A to 2260 A is a t t r i b u t e d to AsP. The system is s t r o n g l y perturbed with an upper s t a t e frequency of about 330 cm The (26I 0 0 spectrum observed by Yee and Jones (3000 A to 3225 A) and assigned to AsP was not detected. Two systems have been a t t r i b u t e d o o to PSb. System 1 (3470 A to 369O A) is in good agreement with that (27) 0 0 reported by Yee, Jones and Kopp 7 . System 2 (2420 A to 2640 A) is more intense than system 1 and i s very s t r o n g l y perturbed with a l i k e l y upper s t a t e frequency of approximately 270 cm '. No v i b r a t i o n a l a n a l y s i s was p o s s i b l e . Only one system of AsSb was (27) observed. This is the same system a t t r i b u t e d by Yee and Jones to AsSb (A^Jl -«- x'z ). The upper s t a t e v i b r a t i o n a l constants were eva1uated. The spectrum of PSb is made up of two red degraded o o systems. System 1 (3470 A to 3690 A) was a l s o observed by Yee, (27) 0 0 Jones, and Koppv 7 . System 2 (2420 A and 2640 A) i s much more intense than system 1 and was not observed by Yee in emission. - kh -The upper states of both systems show perturbations in the v i b r a t i o n a l l e v e l s . (28) Only one system of AsSb was observed. Yee and Jones determined the lower s t a t e v i b r a t i o n a l constants from emission while we measured the upper s t a t e v i b r a t i o n a l c o nstants. In a d d i t i o n to the mixed group V diatomics a new spectrum 0 0 3 3 -between 2030 A and 2200 A a t t r i b u t e d to PC 1 (A IT +• XT, ) was found. o o Accompanying t h i s spectrum is the system of bands (2300 A to 2500 A) a t t r i b u t e d to PCI by Basco and Yee^'^ a n c| a number of unassigned bands between these two systems. These unassigned bands are p o s s i b l y due to PCI or perhaps PC1_. - 45 -BlBLIOGRAPHY 1. G. Po r t e r ; Proc. Roy. S o c , A200, 284 (1950) 2. R.G.W. N o r r i s h , G. Porter and B.A. Thrush; Proc. Roy. S o c , A216, 165 (1953) 3. R.G.W. N o r r i s h ; Proc. Chem. S o c , 247 (1958) 4. R.G.W. N o r r i s h ; Chemistry in B r i t a i n , 289 (1965) 5. G. Po r t e r ; "Techniques of Organic Chemistry", edited by A. Weissberger, 2nd e d i t i o n , Volume V I I I , part 11, Chapter XIX, (I n t e r s c i e n c e , New York, 1963) 6. R.G.W. Nor r i s h and B.A. Thrush; Quart. Revs.,_M3, 149 (1956) 7- N. Basco and R.G.W. N o r r i s h ; Proc. Roy. S o c , A260, 293 (1961) 8. Twyman and Smith; "Wavelength Tables f o r Spectrum A n a l y s i s " , 2nd e d i t i o n , (Adam H i l g e r , London, England, 1930 9- "Handbook of Chemistry and P h y s i c s " , e d i t e d by C D . Hodgman, 43rd e d i t i o n (Chemical Rubber P u b l i s h i n g Co., Cl e v e l a n d , Ohio, 1961) 10. "Table of Wavenumbers", Volume 1, National Bureau of Standards Monograph 3 , U.S. Government P r i n t i n g O f f i c e , Washington, D.C. 11. Corning Glass Works, B u l l e t i n CF-1, Corning, New York 12. M. Kasha; J . Opt. S o c , 38_, ?29 (1948) 13- S.R. Gunn, W.L. J o l l y and L.G. Green; J . Phys. Chem., 64_, 1334 (i960) 14. C.E. Moore; "Atomic Energy L e v e l s " , Volumes I - I I I , U.S. Government National Bureau of Standards C i r c u l a r 467, Volume 1 (1949) - 46 -Vol . II (1952) , Vol . M l (1958) 15- K.K. Yee; Ph.D. T h e s i s , U n i v e r s i t y of B r i t i s h Columbia, (I967) 16. N. Basco and K.K. Yee; Chem. Comm., 1146 (1967) 17- R.N. Dixon and H.M. Lamberton; J . Mol. Spect., 25, 12 (1968) 18. R.N. Dixon, G. Duxbury and H.M. Lamberton; Proc. Roy. S o c , A305, 271 (1968) 19. G.M. Almy and G.D. Kinzer; Phys. Rev., 47, 721 (1935) 20. P. Perdigon and J . D'lncan; Can. J . Phys., 48, 1140 (1970) 21. N. Basco and K.K. Yee; Chem. Comm., 1255 (1967) 22. A.B. C a l l e a r and R.J. Oldman; Trans. Faraday S o c , 64, 840 (1968) 23. S.M. Naude; S. A f r i c a n J . Science XXXII, 103 (1935) 24. G. Nakamura and T. S h i d e i ; Jap. J . Phys., )0_, 11 (1934) 25. N. Basco and K.K. Yee; Spect. L e t t . , J_, 19 (1968) 26. K.K. Yee and W.E. Jones; Chem. Comm., 586 (1969) 27. K.K. Yee, W.E. Jones and I. Kopp; J . Mol. S p e c , 33,119 (1970) 28. K.K. Yee and W.E. Jones; Chem. Comm., 752 (1969) 29. A.E. Douglas and M. Frackowisk; Can. J . Phys., 40, 832 (1962) 30. R. C o l i n and W.E. Jones; Can. J . Phys., 4_5_, 301 (1967) 31. G. Herzberg; "Spectra of Diatomic Molecules", Second e d i t i o n , (D. Van Nostrand Co. (Canada) L t d . , 1950) 32. R.F. Barrow and R.P. Du Parcq; J . Phys. B., 283 (1968) 33- H.W. M e l v i l l e ; Proc. Roy. S o c , Al 38, 374 (1932) 34. H.W. M e l v i l l e ; Proc. Roy. S o c , Al 39, 541 (1933) - 47 -35- R.G.W. Norri s h and G.A. Oldershaw; Proc. Roy, S o c , A262, 1 (1961) 3 6 . N. Basco and K.K. Yee; Spect. L e t t . , J_, 13 (1968) 37- A.G. Briggs and R.G.W. N o r r i s h ; Proc. Roy. S o c , A278, 27 (1964) 3 8 . N. Basco and K.K. Yee; Nature 2 1 6 , 998 (1967) 39- G. Herzberg; " E l e c t r o n i c Spectra of Polytomic Molecules", (D. Van Nostrand Co. Inc., New York, 1 9 6 6 ) 40. F. Legay; Can. J . Phys., 3 8 , 797 ( i 9 6 0 ) 41. F. Creutzberg; Can. J. Phys., 44_, 1583 (1966) 42. G. Herzberg; Ann. Phys. Lpz., J_5_, 677 (1932) 4 3 . C.N. Hinshelwood and B. Topley; J . Chem. S o c , 125, 393 (1924) - 48 -APPENDIX TABLE 11. L i s t of PI Atomic T r a n s i t i o n s Observed in Absorption and Emission (14) Trans i t i on A ( a i r ) A 4S 2P 1/2 4S 2P 3/2 4S 2P 1/2 4S 2P 3/2 - 4 2 3p P + , 4 2 D 3p P 3/2 1/2 ^ 2°3/2 3 ^ \ , 1 3 2 3p> P 1/2 3P 3 2P5 / 2 3 2 D 0 3 P" P 3P 3 2P 1/2 3/2 4S' 2D «- 3 P 3 2P 1/2 3 D3 2P° 3P f3 / 2 3 D 3 2P° 3 D 3 2P° 0 3 2 Do 3 P P 3 / 2 3 P 3 2P° 1/2 2149-11 2135.47 2136.20 2553.28 2554.93 2534.01 2535.65 2152.95 2154.08 2032.37 2033.48 2024.54 2023.47 (vac) cm -1 46515 46812 46797 39155 39129 39452 39426 46435 46409 49187 49161 49378 49404 ^Not observed by Yee^'"^ - ks -TABLE 12. (14) L i s t of As I Atomic T r a n s i t i o n s Observed in Absorption and Emission  Trans i t i on A ( a i r ) A v (vac) cm T5S 4 p 1 / 2 ^ > 4p 3 2 D ° / 2 2492.95 40101 +5S V _,,<-»• 4 P 3 2 D ° 2456.56 40695 3/2 5/2 '5/2 * ^ % 2 '3/2 ~ 2 [ >V2 )° 5/2 1/2 " K J3/2 Z » n3 2P ° 3/2 4 p r l / 2 )° 3/2 1/2 " p ''1/2 >° 3/2 +5S V / 0 «- 4 P 3 2 D ° 0 2381.19 41983 +5S V / 0 4p 3 2 D ° 2271.40 44012 4p3 2 D ° 2288.12 43690 T5S 2 P W , 4p3 2 D ° 2349.84 42543 J5S 2 P _ , „ ^ 4p3 2 P ° . 2745.00 36419 4p 3 2 P ° 2780.22 35957 5S 2 P 1 / 0 ^ 4p3 2 P ° 2860.44 34950 4p 3 2 P ° > 0 2898.71 34488 2 5 S ' D3/2 4 P 3 2 P ° / 2 2344.03 42649 • 4p3 2 P ° / 2 2369.67 42187 5S' 2 D 5 / 2 " 2370.77 42167 Not observed by Y e e ^ ^ i n absorption or emission. Observed by Yee in absorption but not in emission, - 50 -TABLE 12.(continued) L i s t of As I Atomic T r a n s i t i o n s Observed in Absorption and Emission T rans i t i on A ( a i r ) A v (vac) cm f4d 2P3 / 2 <- 4p 3 2P °/ 2 2069.77 48299 Upk 2P3 / 2 +• 4p 3 2P °/ 2 2165.51 46164 + 11 +• 4p 3 2P °/ 2 2144.04 46626 + 4 p 4 2P] / 2 ^ 4p 3 2P °/ 2 2113.00 47311 + 4p/* 2 S ] / 2 *• 4p 3 2P °/ 2 2065.28 48402 +6S kP]/2 * 4p 3 2P °/ 2 2047.56 48823 + " «- 4p 3 2P° 2067-12 48361 'Not observed by Yee in absorption or emission. - 51 -TABLE 13. L i s t of Sbl Atomic T r a n s i t i o n s Observed in Absorption and Emission Trans i t ion X ( a i r ) A v (vac) cm 6S kP]/2 +• 5p 3 kS °3 / 2 2311 .47 43249 6S V3 /2 <- 5p 3 kS° _ 2175.81 45945 3/2 1/2 '' ^ J3/2 6S 2 P ./ 0 5P 3 2 D ° . 2598.05 38479 6S 2P3 / 2 ^ " 2445.51 40879 6S 2P3 / 2 5P 3 2 D ° / 2 2528.52 39537 5/2 11 2293.44 43589 3/2 «- 11 2288.98 43674 5/2 «- " 2208.45 45267 6S V / 0 5P 3 2 D ° , 2877.92 34737 1/2 J V "1/2 3/2 3 2 i - i Co-" r, '5/2 5/2 55/2 ' ^  "5/2 6S \> _ " 2670.64 37433 5P 3 V / 0 2769.95 36091 6S \ > „ -M- 11 2598.08 38478 6S' 2 D R / „ 5P 3 2 D ° „ 2179.19 45874 - 52 -TABLE 13. (continued)  L i s t of SbI Atomic T r a n s i t i o n s Observed in Absorption and Emission (^)^5) ° -1 Trans i t ion X ( a i r ) A v (vac) cm 6S 2 P ] / 2 5 P 3  2P ° ] / 2 3267-51 30596 6S 2 P 3 / 2 «- " 3029-83 32996 3/2 + " 2692.25 37133 6S 2 P 3 / 2 ^ 5P3 2P° / 2 3232.52 30927 3/2 +- " 2851.11 35064 5/2 " .2727.23 36656 6 S 4 pi / 2 * 5 p 3 2 pi / 2 3722.79 26854 6S k?3/2 +• " 3383.15 29550 6S kP3/2 +• 5 P 3 2P° 3 / 2 3637.83 27481 6S' 2D 3 / 2^ 5P3 2P° / 2 2574.06 38838 1/2 " 2480.44 40303 3/2 *• " 2478.32 40338 6S1 2D 3 / 2 *• 5 P 3 2P° / 2 2718.90 36769 - 53 -TABLE 13. (continued) L i s t of Sbl Atomic T r a n s i t i o n s Observed in Absorption and Emission (^)^5) ° -1 Trans i t ion A ( a i r ) A v (vac) cm 6S' 2D 3 / 2 «- 5p 3 2P° / 2 2682.76 37264 3/2 *- 11 2652.60 37688 1/2 «- 11 2614.73 38233 3/2 «- " 2612.31 38269 3/2 + 5p 3 2P ° / 2 2201.32 45413 7 S 2 pi / 2 "~ 5 p 3 2 p3/2 2329.10 42921 5/2 «• " 2315.89 43167 3/2 "- 2306.40 43344 5/2 -r " 2270.08 44038 7S k?]/2 5P 3 2P° / 2 2426.35 41202 1/2 " 2395.21 41737 3/2 <- 11 2360.50 42351 1/2 «- 11 2306.46 43343 3/2 " 2262.51 44185 - 54 -TABLE 13- (continued) L i s t of Sbl Atomic T r a n s i t i o n s Observed in Absorption and Emission ( ^ ^ 5 ) Trans i t i on A ( a i r ) A v (vac) cm 7S V ] / 2 +• 5P 3 2 P ° / 2 2554.64 39133 7S \> / 2 + " 2352.21 42500 3/2 «- " 2481.74 40282 5/2 *• " 2474.54 40499 1/2 +• " 2422.13 41273 5/2 <- 11 2383.64 41940 3/2 *• " 2373-67 42116 F i g u r e 10. E m i s s i o n Spectrum o f P Atom [A. P H ^ A r : 0 . 2 / 5 0 t o r r , B . P H / A r : 0 . 0 2 / 5 t o r r ] F i g u r e 12. E m i s s i o n Spectrum of As Atom [AsH /Ar:0.2/50 t o r r ] Figure 13- Absorption Spectrum of Sb Atom [SbH /Ar:0.k/250 torr,k.8 ps delay] Figure 14. Emission Spectrum of Sb Atom [SbH,/Ar:2/250 t o r r ] - 61 -TABLE 14. Band Heads of the P,, (OX) Spectrum Observed in Absorption V V v cm (obs.) v cm (ca 1 .) 6 0 49538 49537 5 0 49090 49091 6 1 48760 48762 4 0 48639 48640 5 1 48314 48316 3 0 48181 48185 4 1 47870 47866 2 0 47729 47725 3 1 47407 47410 1 0 47264 47260 2 1 46955 46950 Calculated using v i b r a t i o n a l constants reported by Creutzberg. Figure 15. Absorption Spectrum of P [PH /Ar:1/250 torr,110 us delay] - 63 -TABLE 15. Band Heads of the P^ (OX) Spectrum Observed in Emis s i o n7 V V v cm (obs.) v cm v cm (ca 1 .) 4 19 34916 34917 3 18 35127 35130 5 19 35363 35361 4 18 35589 35585 3 17 35792 35797 5 18 36032 36033 4 17 36263 36259 3 16 36488 36486 5 17 36700 36703 4 16 36933 36933 6 17 37151 37156 3 15 37174 37173 5 16 37387 37384 2 ]k 37412 37411 4 15 37617 37613 1 13 37644 37639 6 16 37837 ' 37838 3 14 37864 37865 2 13 38112 38110 1 12 38344 38346 6 15 38527 38522 3 13 38553 38557 3 16 38716 38718 5 14 38770 38770 2 12 38813 38814 13 39015 39018 'Also observed by Yee. ('5 ) Calculated using v i b r a t i o n a l constants reported by Creutzberg. - 64 -TABLE 15. (continued) Band Heads of the (C-»X) Spectrum Observed in Emission V V v cm (obs.) v cm v cm (ca 1 .) 1 11 39057 39055 0 10 39308 39303 7 14 39657 39658 1 10 39776 39772 3 11 39977 39979 0 9 40022 40022 4 11 40427 40433 1 9 40497 40496 3 10 40695 40698 0 8 40745 40747 0 7 41491 41490 5 10 41601 41597 2 8 41700 41695 7 11 41770 41771 4 9 41873 41874 6 10 42048 42046 3 8 42139 42141 0 6 42222 42227 2 7 42423 42427 4 8 42603 42601 6 9 42768 42768 0 5 42974 42975 ^Also observed by Y e e . ^ ^; (41) Calculated using v i b r a t i o n a l constants reported by Creutzberg. Figure 16.Emission Spectrum of P [PH /Ar:l/250 torr] 

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