Vacuum ultraviolet photodissociation and photoionization studies of CH sub 3 SH and SH

Journal Article · Mon Jul 15 00:00:00 EDT 1991 · Journal of Chemical Physics; (USA)

DOI:https://doi.org/10.1063/1.461103· OSTI ID:5683773

Nourbakhsh, S; Norwood, K; Yin, H; Liao, C; Ng, C Y ^[1]

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1. Ames Laboratory, U.S. Department of Energy and Department of Chemistry, Iowa State University, Ames, Iowa 50011 (USA)

The kinetic energy releases of the photodissociation processes, CH{sub 3}SH+{ital h}{nu} (193 nm){r arrow}CH{sub 3}+SH, CH{sub 3}S+H, and CH{sub 2}S+H{sub 2}, have been measured using the time-of-flight mass spectrometric method. These measurements allow the direct determination of the dissociation energies for the CH{sub 3}--SH and CH{sub 3}S--H bonds at 0 K as 72.4{plus minus}1.5 and 90{plus minus}2 kcal/mol, respectively. The further dissociation of SH according to the process SH+{ital h}{nu} (193 nm){r arrow}S+H has also been observed. The appearance energy (AE) of S produced in the latter process is consistent with the formation of S({sup 3}{ital P})+H. The photoelectron--photoion coincidence (PEPICO) spectra for CH{sub 3}SH{sup +}, CH{sub 3}S{sup +} (or CH{sub 2}SH{sup +}), and CH{sub 2}S{sup +} from CH{sub 3}SH have been measured in the wavelength range of 925--1460 A. The PEPICO measurements make possible the construction of the breakdown diagram for the unimolecular decomposition of internal-energy-selected CH{sub 3}SH{sup +} in the range of 0--83 kcal/mol. The AE measured for CH{sub 2}S{sup +} is consistent with the conclusion that the activation energy is negligible for 1,2-H{sub 2} elimination from CH{sub 3}SH{sup +}.

• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 5683773
• Journal Information: Journal of Chemical Physics; (USA), Vol. 95:2, Issue 2; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ORGANIC SULFUR COMPOUNDS
DISSOCIATION
PHOTOIONIZATION
ACTIVATION ENERGY
DECOMPOSITION
TIME-OF-FLIGHT METHOD
ULTRAVIOLET SPECTRA
CHEMICAL REACTIONS
ENERGY
IONIZATION
ORGANIC COMPOUNDS
SPECTRA
400500* - Photochemistry
400201 - Chemical & Physicochemical Properties