Go to  Advanced Search

Optical and infrared spectra of some unstable molecules

Show full item record

Files in this item

Files Size Format Description   View
UBC_1988_A1 B37.pdf 13.28Mb Adobe Portable Document Format   View/Open
 
Title: Optical and infrared spectra of some unstable molecules
Author: Barry, Judith Anne
Degree Doctor of Philosophy - PhD
Program Chemistry
Copyright Date: 1987
Subject Keywords Molecular spectra; Infrared spectroscopy
Abstract: Some unstable gaseous molecules, cobalt oxide (CoO), niobium nitride (NbN) and aminoborane (NH₂BH₂), were studied by high resolution optical spectroscopy. A portion of the "red" system of CoO, from 7000 Å to 5800 Å, was measured using laser induced fluorescence techniques. Three bands of the system, with origins at 6338 Å, 6411 Å and 6436 Å, were rotationally analyzed. The lower levels of these parallel bands are the Ω = 7/2 and 5/2 spin-orbit components of a ⁴∆i electronic state. Available evidence indicates that this is the ground state of the molecule; its bond length is 1.631 Å. This work completes the determination of the ground state symmetries for the entire series of first row diatomic transition metal oxides. The hyperfine structure in the ground state is very small, supporting a σ²δ³π² electron configuration. The upper state, assigned as σδ³π²σ*, has large positive hyperfine splittings that follow a case (aβ) pattern; it is heavily perturbed, both rotationally and vibrationally. The sub-Doppler spectrum of the ³Φ₋³∆ system of NbN was measured by intermodulated fluorescence techniques, and the hyperfine structure analyzed. Second order spin-orbit interactions have shifted the ³Φ₃₋³∆₂ subband 40 cm⁻¹ to the blue of its central first order position. The perturbations to the spin-orbit components were so extensive that five hyperfine constants, rather than three, were required to fit the data to the case (a) Hamiltonian. The ³∆₋³Φ system of NbN is the first instance where this has been observed. The magnetic hyperfine constants indicate that all components of the ³∆ and ³Φ spin orbit manifolds may be affected, though the ³∆ state interacts most strongly, presumably by the coupling of the ³∆₂ component with the ¹∆ state having the same configuration. The Fermi contact interactions in the ³∆ substates are large and positive, consistent with a σ¹δ¹ configuration. In the ³Φ state the (b + c) hyperfine constants are negative, as expected from a π¹δ¹ configuration. The ³∆ and ³Φ bond lengths are 1.6618 Å and 1.6712 Å, respectively, which are intermediate between those of ZrN and MoN. The Fourier transform infrared spectrum of the V7 BH₂ wagging fundamental of NH₂BH₂ was rotationally analyzed. A set of effective rotational and centrifugal distortion constants was determined, but the band shows extensive perturbations by Coriolis interactions with the nearby V5 and V11 fundamentals. A complete analysis could not be made without an analysis of the V5-V7-V11 Coriolis interactions, which is currently not possible because the very small dipole derivative of the V5 vibration has prevented its analysis.
URI: http://hdl.handle.net/2429/28619
Series/Report no. UBC Retrospective Theses Digitization Project [http://www.library.ubc.ca/archives/retro_theses/]
Scholarly Level: Graduate

This item appears in the following Collection(s)

Show full item record

All items in cIRcle are protected by copyright, with all rights reserved.

UBC Library
1961 East Mall
Vancouver, B.C.
Canada V6T 1Z1
Tel: 604-822-6375
Fax: 604-822-3893