University of Illinois Urbana-Champaign

Electronic transitions of tungsten monosulfide

Cheung, Allan S.C.

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2284.pdf
838228.pptx

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https://hdl.handle.net/2142/97034

Description

Title
Electronic transitions of tungsten monosulfide
Author(s)
Cheung, Allan S.C.
Contributor(s)
  • Zou, Wenli
  • Chan, Man-Chor
  • Tsang, L.F.
Issue Date
2017-06-21
Keyword(s)
Metal containing
Date of Ingest
  • 2017-07-27T20:15:34Z
  • 2018-01-29T23:05:56Z
Abstract
Electronic transition spectrum of the tungsten monosulfide (WS) molecule in the near infrared region between 725 nm and 885 nm has been recorded using laser ablation/reaction free-jet expansion and laser induced fluorescence spectroscopy. The WS molecule was produced by reacting laser - ablated tungsten atoms with 1% CS$_{2}$ seeded in argon. Fifteen vibrational bands with resolved rotational structure have been recorded and analyzed, which were organized into seven electronic transition systems. The ground state has been identified to be the X$^{3}$$Sigma$$^{-}$(0$^{+}$) state, and the determined vibrational frequency, $Delta$G$_{1/2}$ and bond length, r$_{0}$, are respectively 556.7 cm$^{-1}$ and 2.0676 AA. In addition, vibrational bands belong to another transition system involving lower state with $Omega$ = 1 component have also been analyzed. Least-squares fit of the measured line positions yielded molecular constants for the electronic states involved._x000d_ _x000d_ The low-lying $Lambda$-S states and $Omega$ sub-states of WS have been calculated using state-averaged complete active space self-consistent field (SA-CASSCF) and followed by MRCISD+Q (internally contracted multi-reference configuration interaction with singles and doubles plus Davidson’s cluster correction). The active space consists of 10 electrons in 9 orbitals corresponding to the W 5d6s and S 3p shells. The lower molecular orbitals from W 5s5p and S 3s are inactive but are also correlated, and relativistic effective core potential (RECPs) are adopted to replace the core orbitals with 60 (W) and 10 (S) core electrons, respectively. Spin-orbit coupling (SOC) is calculated via the state-interaction (SI) approach with RECP spin-orbit operators using SA-CASSCF wavefunctions, where the diagonal elements in the SOC matrix are replaced by the corresponding MRCISD+Q energies calculated above. Spectroscopic constants and potential energy curves of the ground and many low-lying $Lambda$-S states and $Omega$ sub-states of the WS molecule are obtained. The calculated spectroscopic constants of the ground and low-lying states are generally in good agreement with our experimental determination. This work represents the first experimental investigation of the electronic and molecular structure of the WS molecule._x000d_
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
text
Genre of Resource
Conference Paper / Presentation
Language
eng
Permalink
http://hdl.handle.net/2142/97034
DOI
https://doi.org/10.15278/isms.2017.WK03
Copyright and License Information
Copyright 2017 Allan S.C. Cheung

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Abstracts & Presentations - 2017 International Symposium on Molecular Spectroscopy PRIMARY