THE MOLECULAR STRUCTURE AND RENNER-TELLER EFFECT IN THE ELECTRONIC SPECTRUM OF BORON DISULFIDE, $BS_{2}$
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Date
2003
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Publisher
Ohio State University
Abstract
The $\tilde{A} ^{2}\Pi_{u} - \tilde{X} ^{2}\Pi_{g}$ electronic band system of jet-cooled boron disulfide has been studied by laser-induced fluorescence and wavelength resolved emission spectroscopy. The free radical was produced in a pulsed electric discharge jet using a precursor mixture of $BCl_{3}$ and $CS_{2}$ in argon. Detailed analysis of the spectra shows that the ground state exhibits a substantial Renner-Teller effect with $\epsilon = -0.2013$ and a spin-orbit coupling constant $A = -413.80 cm^{-1}$. Angular momentum coupling is negligible in the excited state which has a much smaller spin-orbit coupling constant of $A = -239.15 cm^{-1}$. Rotational analysis of the $0_{0}^{0}$ band gave the effective molecular structures as $r_{0}^{\prime\prime} = 1.6648(4) \AA$ and $r^{\prime}_{0} = 1.7127(5) \AA$. Ab initio methods have been used to predict the $BS_{2}$ spectroscopic parameters and good agreement with experiment was found. Our present understanding of the LIF spectrum is in accord with the pioneering analysis of the absorption spectrum of matrix isolated $BS_{2}$ published by Brom and $Weltner^{a}$ three decades ago.
Description
$^{a}$ J.M.Brom, Jr. and W. Weltner, Jr., J. Mol. Spectrosc. 45, 82 (1973).
Author Institution: Department of Chemistry, University of Kentucky
Author Institution: Department of Chemistry, University of Kentucky