{ital Ab initio} study of the O{sub 2}(X{sup 3}{Sigma}{sub g}{sup {minus}})+Ar({sup 1}S) van der Waals interaction
- Department of Chemistry, Miami University, Oxford, Ohio 45056 (United States)
- High Performance Computational Chemistry Group, Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352-0999 (United States)
- Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warszawa (Poland)
- Department of Chemistry, Oakland University, Rochester, Michigan 48309 (United States)
A potential energy surface for the Ar({sup 1}S)+O{sub 2}(X{sup 3}{Sigma}{sub g}{sup {minus}}) interaction is calculated using the supermolecular unrestricted Mo/ller{endash}Plesset (UMP) perturbation theory and analyzed via the perturbation theory of intermolecular forces. The global minimum occurs for the T-shaped geometry, around 6.7a{sub 0}. Our UMP4 estimate of the well depth of the global minimum is D{sub e}=117cm{sup {minus}1} and the related ground state dissociation energy obtained by diffusion Monte Carlo calculations is 88cm{sup {minus}1}. These values are expected to be accurate to within a few percent. The potential energy surface also reveals a local minimum for the collinear geometry at ca{approximately}7.6a{sub 0}. The well depth for the secondary minimum at the UMP4 level is estimated at D{sub e}=104cm{sup {minus}1}. The minima are separated by a barrier of 23cm{sup {minus}1}. The global minimum is determined by the minimum in the exchange repulsion in the direction perpendicular to the O{endash}O bond. The secondary, linear minimum is enhanced by a slight flattening of the electron density near the ends of the interoxygen axis. {copyright} {ital 1997 American Institute of Physics.}
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 565267
- Journal Information:
- Journal of Chemical Physics, Vol. 106, Issue 18; Other Information: PBD: May 1997
- Country of Publication:
- United States
- Language:
- English
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