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 +]

Journal Article · Sun Nov 01 04:00:00 EST 1992 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.463659· OSTI ID:6966815

Chiu, S ^[1]; Li, W ^[2]; Tzeng, W; Ng, C ^[3]

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1. Biotechnology Center, University of Illinois, Urbana, Illinois 61801 (United States) National Center for Supercomputing Applications, University of Illinois, Champaign, Illinois 61820 (United States)
2. Department of Chemistry, The Chinese University of Hong Kong, Shatin, N. T. (Hong Kong)
3. 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), Journal Name: Journal of Chemical Physics; (United States) Vol. 97:9; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

664100* -- Theory of Electronic Structure of Atoms & Molecules-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ANIONS
CATIONS
CHARGED PARTICLES
FUNCTIONS
GAUSS FUNCTION
HYDROCARBONS
IONS
MOLECULAR STRUCTURE
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
TOTAL ENERGY SYSTEMS