AB INITIO STUDY OF GROUND-STATE CS PHOTODISSOCIATION VIA HIGHLY EXCITED ELECTRONIC STATES

Xu, Zhongxing

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https://hdl.handle.net/2142/104381 Copy

Description

Title

AB INITIO STUDY OF GROUND-STATE CS PHOTODISSOCIATION VIA HIGHLY EXCITED ELECTRONIC STATES

Author(s)

Xu, Zhongxing

Contributor(s)

Crabtree, Kyle N.; Wang, Lee-Ping ; Federman, Steven ; Ng, Cheuk-Yiu ; Jackson, William M.; Luo, Nan

Issue Date

2019-06-19

Keyword(s)

Electronic structure, potential energy surfaces

Abstract

"Wavelength-dependent photodissociation cross sections are key data required by modern astrochemical models to simulate the evolution of chemical species in photon-dominated regions. Although photodissociation is considered as the dominant destruction pathway for carbon monosulfide (CS) in these enviroments, the photodissociation rate pf CS is essentially unknown due to a lack of vacuum ultraviolet (VUV) laboratory measurements and accurate theoretical calculations. Here we present a high-level \textit{ab initio} study of CS photodissociation, including for the first time a detailed investigation of its predissociation via the \(B\,^1\Sigma^+\) and \(C\,^1\Sigma^+\) states. Potential energy curves of CS electronic states were calculated at the MRCI+Q/aug-cc-pV(5+C)Z level and photodissociation cross sections from the vibrational and electronic ground state were calculated by solving the coupled-channel Schr\""{o}dinger equation. We found that the \(C-X\) \((0-0)\) transition followed by spin-orbit coupling into several triplet states is responsible for 73\% of the overall photodissociation of CS under the standard interstellar radiation field (ISRF), giving rise to the main atomic products C (\(^3P\)) and S (\(^1D\)). Our new calculations of the photodissociation rate are a factor of 2.4 larger than the value currently adopted by the Leiden database, suggesting that this value may be revised for improving the accuracy of astrochemical models."

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/104381

DOI

10.15278/isms.2019.WD04

Copyright and License Information

Copyright 2019 Zhongxing Xu

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