Effects Of Spin-orbit Coupling On The Spin-rotation Interaction In The Ash2 Radical

Duxbury, Geoffrey

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https://hdl.handle.net/2142/50874 Copy

Description

Title

Effects Of Spin-orbit Coupling On The Spin-rotation Interaction In The Ash2 Radical

Author(s)

Duxbury, Geoffrey

Contributor(s)

Alijah, Alexander

Issue Date

2014-06-18

Keyword(s)

Comparing theory and experiment

Abstract

"The occurence of predissociation in the electronic spectrum of AsH$_{2}$ is very dependent upon the magnitude of the spin-orbit coupling parameter of the central atom. Making use of Table 5.6 in ""The Spectra and Dynamics of Diatomic Molecules, ELSEVIER"" by H. Lefebvre-Brion and R.W. Field, it is possible to appreciate the rapid rate of increase of the spin-orbit constants associated with the heavy central atom in the di-hydrides NH$_{2}$, PH$_{2}$ and AsH$_{2}$. The spin-orbit constants range from 42.7 cm$^{-1}$ for NH$_{2}$, to 191.3 cm$^{-1}$ for PH$_{2}$, and 1178 cm$^{-1}$ for AsH$_{2}$. The effects of spin-orbit coupling may be seen in a plot of the separation of the central $^{R}$Q$_{0,9}$ and $^{P}$Q$_{1,N}$ sub-bands as the value of v$_{2}$' increases from 0 to 5. As the value of v$_{2}$' increases beyond 2 the spectrum becomes more and more fuzzy as the effects of predissociation become more obvious. This means that unlike the example of the behaviour of PH$_{2}$, where the vibronic level pattern can be followed below and above the barrier to linearity, in AsH$_{2}$ and AsD$_{2}$ the absorption spectrum becomes completely diffuse below the barrier to linearity in the A $^{2}$A$_{1}$ state. The change in the magnitude of the doublet splittings as v$_{2}$' increases may be seen in the plots of the doublet splittings showing the spin-uncoupling as a result of the increase of overall rotation. In the absorption spectrum of SbH$_{2}$, recorded in 1967 by T. Barrow in the Chemistry Department at Sheffield University, all the absorption features showed the effects of predissociation, consistent with a spin-orbit constant of 2834 cm$^{-1}$ for the central atom of SbH$_{2}$."

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/50874

DOI

https://doi.org/10.15278/isms.2014.WI03

Copyright and License Information

Copyright 2014 by the authors. Licensed under a Creative Commons Attribution 4.0 International License. http://creativecommons.org/licenses/by/4.0/

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