A study of the S([sup 3][ital P][sub 2,1,0]; [sup 1][ital D][sub 2]) production in the 193 nm photodissociation of CH[sub 3]S([ital [tilde X]])

Journal Article · Sun Nov 01 00:00:00 EST 1992 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.463690· OSTI ID:7016788

Hsu, C; Liao, C; Ma, Z; Tjossem, P J.H.; 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 (United States)

The dynamics of S([sup 3][ital P][sub 2,1,0];[sup 1][ital D][sub 2]) production from the 193 nm photodissociation of CH[sub 3]SCH[sub 3] has been studied using 2+1 resonance-enhanced multiphoton ionization techniques. The 193 nm photodissociation cross section for the formation of S from CH[sub 3]S initially prepared in the photodissociation of CH[sub 3]SCH[sub 3] is estimated to be 1[times]10[sup [minus]18] cm[sup 2]. The branching ratio for S([sup 3][ital P])/S([sup 1][ital D]) is found to be 0.15/0.85. The fine-structure distribution observed for product S([sup 3][ital P][sub 2,1,0]) is nearly statistical. Possible potential energy surfaces involved in the 193 nm photodissociation of CH[sub 3]S([ital [tilde X]]) have been examined theoretically along the CH[sub 3]--S dissociation coordinate in [ital C][sub 3[ital v]] symmetry. These calculations suggest that predissociation of CH[sub 3]S([ital [tilde C]] [sup 2][ital A][sub 2]) via the repulsive CH[sub 3]S([ital [tilde E]] [sup 2][ital E]) surface is most likely responsible for the efficient production of S([sup 1][ital D]). For vibrationally excited CH[sub 3]S([ital [tilde X]]), a viable mechanism for the dominant production of S([sup 1][ital D]) may involve direct dissociation via the CH[sub 3]S([ital [tilde E]] [sup 2][ital E]) state formed in the 193 nm photoexcitation.

• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 7016788
• Journal Information: Journal of Chemical Physics; (United States), Vol. 97:9; ISSN 0021-9606
• Country of Publication: United States
• Language: English

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