Photodissociation spectroscopy and dynamics of the methylthio radical (CH{sub 3}S)
- Department of Chemistry, University of California, Berkeley, California 94720 (United States)
The photodissociation spectroscopy and dynamics of the CH{sub 3}S and CD{sub 3}S radicals have been investigated using fast radical beam photofragment spectroscopy of the {tilde A}thinsp{sup 2}A{sub 1}{l_arrow}{tilde X}thinsp{sup 2}E electronic band (T{sub 0}{congruent}26thinsp400thinspcm{sup {minus}1}) and an unstructured band near 45thinsp600 cm{sup {minus}1}. At all energies, only one major channel, CH{sub 3}({tilde X}thinsp{sup 2}A{sub 2}{sup {double_prime}})+S({sup 3}P{sub j}), was observed. Photofragment yield spectra for the {tilde A}thinsp{sup 2}A{sub 1}{l_arrow}{tilde X}thinsp{sup 2}E electronic band show resolved vibrational progressions extending well beyond those seen in laser-induced fluorescence studies of this band. Photofragment translational energy distributions yield the S({sup 3}P{sub j}) fine-structure distribution for each vibrational level of the CH{sub 3} product. Photofragment angular distributions were found to be highly anisotropic ({beta}={minus}0.2 to {minus}1.0{plus_minus}0.1) with increasing anisotropy at higher photon energies. The results yield a refined heat of formation for CH{sub 3}S (1.346{plus_minus}0.018 eV) as well as the mechanism by which the {tilde A}thinsp{sup 2}A{sub 1} state is predissociated. Results at 45thinsp600 cm{sup {minus}1} imply that dissociation occurs on the repulsive {tilde B}thinsp{sup 2}A{sub 2} state. {copyright} {ital 1999 American Institute of Physics.}
- OSTI ID:
- 289230
- Journal Information:
- Journal of Chemical Physics, Vol. 110, Issue 2; Other Information: PBD: Jan 1999
- Country of Publication:
- United States
- Language:
- English
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