Excited potential energy surfaces of CH[sub 3]SH from the [ital ab] [ital initio] effective valence shell Hamiltonian method
- The James Franck Institute and the Department of Chemistry, The University of Chicago, Chicago, Illinois 60637 (United States)
- Cray Research, Inc., Egan, Minnesota 55123 (United States)
The ground and first and second [sup 1][ital A][double prime] potential surfaces of methyl mercaptan (CH[sub 3]SH) are calculated as a function of the C--S and S--H bond coordinates using the [ital ab] [ital initio] effective valence shell Hamiltonian ([ital H][sup [nu]]) method. The computations for this highly nontrivial system provide the first serious tests for choosing restricted valence spaces and for computing global potential energy surfaces with the [ital H][sup [nu]] methods. The quasidegeneracy constraints on the [ital H][sup [nu]] method suggest choosing a valence space which consists of the two (3[ital a][double prime] and 10[ital a][prime]) highest energy occupied orbitals in the ground state and the three lowest [ital a][prime] unoccupied orbitals. The global potential surfaces are computed with a modest basis, but larger basis set computations at selected geometries test convergence for vertical excitation energies, ionization potentials, and C--S and S--H bond energies. The calculations are compared to both experiment and other calculations for this system. The computations assist in the interpretation of CH[sub 3]SH photodissociation dynamics observed by Butler and co-workers.
- DOE Contract Number:
- FG02-92ER14305
- OSTI ID:
- 7141601
- Journal Information:
- Journal of Chemical Physics; (United States), Vol. 101:6; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
THIOLS
POTENTIAL ENERGY
BINDING ENERGY
CHEMICAL BONDS
EXCITED STATES
GROUND STATES
HAMILTONIANS
ENERGY
ENERGY LEVELS
MATHEMATICAL OPERATORS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
QUANTUM OPERATORS
664100* - Theory of Electronic Structure of Atoms & Molecules- (1992-)