A Gaussian-2 [ital ab] [ital initio] study of CH[sub 2]SH, CH[sub 2]S[sup [minus]], CH[sub 3]S[sup [minus]], CH[sub 2]SH[sup [minus]], CH[sub 3]SH[sup [minus]], CH[sub 3][sup +], and CH[sub 3]SH[sup +]
- Biotechnology Center, University of Illinois, Urbana, Illinois 61801 (United States) National Center for Supercomputing Applications, University of Illinois, Champaign, Illinois 61820 (United States)
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N. T. (Hong Kong)
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 10706 (United States)
Using the Gaussian-2 (G2) theoretical procedure, we have examined the molecular structures and total energies for CH[sub 2]SH, CH[sub 2]S[sup [minus]], CH[sub 3]S[sup [minus]], CH[sub 2]SH[sup [minus]], CH[sub 3]SH[sup [minus]], CH[sub 3][sup +], and CH[sub 3]SH[sup +]. Contrary to the relative stabilities of CH[sub 3]S[sup +]([ital C][sub 3[ital v]];[sup 3][ital A][sub 2]) and CH[sub 2]SH[sup +]([ital C][sub [ital s]];[sup 1][ital A][prime]), the methylthio radical CH[sub 3]S([ital C][sub [ital s]];[sup 2][ital A][prime]) and the methylthio anion CH[sub 3]S[sup [minus]]([ital C][sub 3[ital v]];[sup 1][ital A][sub 1]) are predicted to be more stable than the mercaptomethyl radical CH[sub 2]SH([ital C][sub 1];[sup 2][ital A]) and the mercaptomethyl anion CH[sub 2]SH[sup [minus]]([ital C][sub [ital s]];[sup 1][ital A][prime]) by 9.2 and 38.0 kcal/mol, respectively. The CH[sub 2]SH[sup [minus]]([ital C][sub [ital s]];[sup 1][ital A][prime]) anion may exist in the [ital cis] configuration or the less stable [ital trans] structure. Combined with the results of previous G2 calculations, this calculation yields predictions for the adiabatic ionization energies (IE) of CH[sub 3] (9.79 eV), CH[sub 2]SH (7.41 eV), and CH[sub 3]SH (9.55 eV), which are in accord with the experimental IEs of 9.84 eV for CH[sub 3], 7.536[plus minus]0.003 eV for CH[sub 2]SH, and 9.440 eV for CH[sub 3]SH. The G2 values for the adiabatic electron affinities (EA) of CH[sub 2]S, CH[sub 2]SH to [ital trans]-CH[sub 2]SH[sup [minus]]([ital C][sub [ital s]];[sup 1][ital A][prime]), CH[sub 2]SH to [ital cis]-CH[sub 2]SH[sup [minus]]([ital C][sub [ital s]];[sup 1][ital A][prime]), and CH[sub 3]S are 0.38, 0.52, 0.61, and 1.86 eV, respectively. The EA(G2)'s of CH[sub 2]S and CH[sub 3]S also agree with the respective experimental values of 0.465[plus minus]0.023, and 1.861[plus minus]0.004 eV.
- OSTI ID:
- 6966815
- 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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