A high-resolution vacuum ultraviolet photoionization, photoelectron, and pulsed field ionization study of CS{sub 2} near the CS{sub 2}{sup +}(X{sup 2}{Pi}{sub 3/2,1/2}) thresholds

Journal Article · Tue Dec 31 23:00:00 EST 1996 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.473967· OSTI ID:459828

Huang, J; Cheung, Y; Evans, M; Liao, C; Ng, C Y ^[1]; Hsu, C; Heimann, P ^[2]; Lefebvre-Brion, H; Cossart-Magos, C ^[3]

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1. Ames Laboratory, USDOE and Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States)
2. Chemical Sciences Division and Advanced Light Source, Accelerator and Fusion Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
3. Laboratoire de Photophysique Moleculaire, Batiment 213, Universite de Paris-Sud 91405 Orsay Cedex (France)

High-resolution photoionization efficiency (PIE) and pulsed field ionization photoelectron (PFI-PE) spectra for CS{sub 2} have been measured using coherent vacuum ultraviolet (VUV) laser radiation in the energy range of 81050{endash}82100 cm{sup {minus}1}. The PIE and threshold photoelectron (TPE) spectra for CS{sub 2} in the energy range of 80850{endash}82750 cm{sup {minus}1} have also been obtained using synchrotron radiation. The analysis of the PIE spectra reveals three Rydberg series converging to the excited CS{sub 2}{sup +}({sup 2}{Pi}{sub 1/2}) spin{endash}orbit state. These series, with quantum defects of 1.430, 1.616, and 0.053, are associated with the [{sup 2}{Pi}{sub 1/2}]np{sigma}{sub u}, [{sup 2}{Pi}{sub 1/2}]np{pi}{sub u}, and [{sup 2}{Pi}{sub 1/2}]nf{sub u} configurations. The Stark shift effect on the ionization threshold of CS{sub 2} has been examined as a function of dc electric fields (F) in the range of 0.65{endash}1071 V/cm. The observed F dependence of the Stark shift for the ionization onset of CS{sub 2} is consistent with the prediction by the classical adiabatic field ionization formula. The extrapolation of the ionization onset to zero F yields accurate values for IE[CS{sub 2}{sup +}({tilde X}{sup 2}{Pi}{sub 3/2})]. In order to determine accurate IEs and to probe autoionizing structures for molecular species by PIE measurements, it is necessary to minimize the electric field used for ion extraction. Assignment of Renner{endash}Teller structures resolved in the VUV PFI-PE spectrum is guided by the recent nonresonant two-photon (N2P) PFI-PE and theoretical studies. Analysis of the PFI-PE spectrum also yields accurate values for IE[CS{sub 2}{sup +}({tilde X}{sup 2}{Pi}{sub 3/2,1/2})]. Taking average of the IE values determined by VUV-PFI-PE, N2P-PFI-PE, and Stark field extrapolation methods, we obtain a value of 81285.7{plus_minus}2.8 cm{sup {minus}1} for IE[CS{sub 2}{sup +}({tilde X}{sup 2}{Pi}{sub 3/2})]. (Abstract Truncated)

• Research Organization: Lawrence Berkeley National Laboratory
• DOE Contract Number: AC03-76SF00098; W-7405-ENG-82
• OSTI ID: 459828
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 3 Vol. 106; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
66 PHYSICS
AUTOIONIZATION
CARBON COMPOUNDS
CARBON SULFIDES
EXTREME ULTRAVIOLET SPECTRA
L-S COUPLING
LASER RADIATION
LINE WIDTHS
MASS SPECTROSCOPY
PHOTOELECTRON SPECTROSCOPY
PHOTOIONIZATION
PHOTON-MOLECULE COLLISIONS
RYDBERG STATES
STARK EFFECT
SYNCHROTRON RADIATION SOURCES
two-photon spectra
vibronic states