UBC Theses and Dissertations
Studies in high resolution spectroscopy Anderson, Darlene
The ground state microwave spectra of hypochlorous acid (HOCl), carbonylchlorofluoride (FClCO), and N-chlorodifluoromethylenimine (CF₂NCI), have been measured from 8 — 80 GHz and analyzed. The 8[sup 2/sub0] vibrational band of aminoborane (NH₂BH₂) near 1223 cm⁻¹ has been recorded at a resolution of 0.004 cm⁻¹ and analyzed. HOCl: Rotational constants and quartic centrifugal distortion constants were obtained for the following four isotopic species of hypochlorous acid: D¹⁶O³⁵Cl, D¹⁶O³⁷Cl, H¹⁸O³⁵Cl and H¹⁸O³⁷Cl. The centrifugal distortion constants were combined with vibrational wavenumbers from the literature to determine a valence harmonic force field which was used to calculate an average structure and an estimated equilibrium structure. Effective and full substitution structures have also been evaluated. FClCO: An extensive set of transitions, to high J and K has been measured for the two most abundant species, F³⁵CI¹²CO and F³⁷CI¹²CO, which allowed accurate values for the rotational constants, centrifugal distortion constants and the chlorine nuclear quadrupole coupling constants to be evaluated for each. An estimate of the three rotational constants for F³⁵CI¹³CO was made from the four transitions measured, as it exists in natural abundance. Harmonic force constants were produced from ab initio calculations and were used in the determination of its harmonic force field. Effective and average structural parameters have been determined. CF₂NCI: Rotational constants and quartic centrifugal distortion constants have been obtained for the two isotopic species CF₂N³⁵CI and CF₂N³⁷CI. The nuclear quadrupole coupling constants of both ¹⁴N and CI have been evaluated. A partial harmonic force field has been determined from the available data. Both effective and average structural parameters have been obtained and indicate that the structure of CF₂NCI is a hybrid of those of CF₂NF and CCl₂NCl. The nuclear quadrupole coupling constants have provided information about the bonding in the molecule. NH₂BH₂: Rotational constants and centrifugal distortion constants of the upper vibrational state 2v₈ have been determined and have confirmed the assignment of the band. The least squares refinement of the constants has shown an increasing poorness of fit to the higher K[sub a] transitions which has suggested the possiblity of Coriolis type perturbations.
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