Collision-induced intensity of the b{sup 1}{Sigma}{sub g}{sup +}-a{sup 1}{triangle}g transition in molecular oxygen: Model calculations for the collision complex O{sub 2} + H{sub 2}
- Uppsala Univ., Cherkassy (Ukraine)
- Uppsala Univ., Uppsala (Sweden)
Ab initio configuration interaction (CI) calculations have been performed for the O{sub 2} + H{sub 2} complex in a trapezoidlike collision arrangement with C{sub 2v} symmetry. The potential energy surfaces of the four lowest states of this van der Waals complex (arising from the X{sup 3}{Sigma}{sub g}{sup +} states of the oxygen moiety), as well as the collision-induced b{sup 1}{Sigma}{sub g}{sup +}-a{sup 1}{triangle}g electric dipole transition moment (M{sub b-a}), have been analyzed for different CI expansions, using as a reference determinant the restricted open-shell Hartree-Fock (ROHF) function for the ground state of the complex H{sub 2}(X{sup 1}{Sigma}{sub g}{sup +}) + O{sub 2}(X{sup 3}{Sigma}{sub g}{sup -}). The geometry optimized at the ROHF/6-311G level was refined by a partial optimization at the CI level scanning intermolecular distance. The equilibrium distances for the X, a, and b states have been found to be a slightly different in the region 3.02-2.98 A. The larger binding energy of the b{sup 1}{Sigma}{sub g}{sup +} state (2.96 kJ/mol) in comparison with the a{sup 1}{triangle}g (2.1 kJ/mol) and ground X{sup 3}{Sigma}{sub g}{sup -} states (1.35 kJ/mol) presumably could be explained as resulting from charge-transfer interactions. A good convergence of the calculated transition moment M{sub b-a} for the larger CI expansions (approximately 50,000 configuration-state functions) has been obtained. The calculated collision-induced intensity of the b{sup 1}{Sigma}{sub g}{sup +} - a{sup 1}{triangle}g and a{sup 1}{triangle}g - X{sup 3}{Sigma}{sub g}{sup -} transitions in molecular oxygen are in reasonable agreement with recent experimental data for several foreign gases.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 160354
- Journal Information:
- International Journal of Quantum Chemistry, Vol. 50, Issue 4; Other Information: PBD: 1994
- Country of Publication:
- United States
- Language:
- English
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