A zero-order picture of the infrared spectra of CH3O and CD3O: Assignment of states

Johnson, Britta

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https://hdl.handle.net/2142/96995 Copy

Description

Title

A zero-order picture of the infrared spectra of CH3O and CD3O: Assignment of states

Author(s)

Johnson, Britta

Contributor(s)

Sibert, Edwin

Issue Date

2017-06-19

Keyword(s)

Multiple potential energy surfaces

Abstract

Experimentalists and theorists alike have been intrigued by the infrared spectra of the methoxy radical; due to the presence of a conical_x000d_ intersection at the C$_{3v}$ molecular geometry,_x000d_ methoxy's IR spectrum is strongly influenced by Jahn-Teller vibronic coupling which_x000d_ leads to large amplitude vibrations and extensive mixing of the two lowest_x000d_ electronic states. This radical's complex IR spectra, which also contains moderate mixing from spin-orbit and Fermi couplings, serves as_x000d_ an important test for models which seek to understand complex molecular vibrations._x000d_ _x000d_ The assignment of the IR spectra in methoxy, and its partially and fully deuterated analogues, is considered._x000d_ All vibronic states below 2575 cm$^{-1}$ in CH$_3$O and 2035 cm$^{-1}$ in CD$_3$O_x000d_ are assigned. _x000d_ The mixing between the zero-order normal modes complicates the assignment using this representation._x000d_ Alternative zero-order representations, that include specific Jahn-Teller couplings, are explored and used to create_x000d_ definitive assignments for the low lying vibronic states. In many instances it is possible to plot the wavefunctions on which the assignments are based. The plots also enable one to visualize the conical seam_x000d_ and its effect on the wavefunctions. The first and second order Jahn-Teller coupling in the rocking motion dominates_x000d_ the spectral features in CH$_3$O, while first order and modulated first order couplings dominate the spectral features in CD$_3$O._x000d_ The methods described here are general and can be applied to other Jahn-Teller systems._x000d_

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/96995

DOI

https://doi.org/10.15278/isms.2017.MG02

Copyright and License Information

Copyright 2017 Britta Johnson

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