ISSN:
0020-7608
Keywords:
Computational Chemistry and Molecular Modeling
;
Atomic, Molecular and Optical Physics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The Generator Coordinate Approximation (GCA) is the general approximation scheme for molecular systems devised to improve the Adiabatic Approximation (AA). This is achieved by replacing the familiar product-type molecular wave function by a convolution product-like state. One can demonstrate via Born-Oppenheimer perturbation theory that for vibration-rotation levels near potential energy minima the GCA results are bracketted by the exact and adiabatic values, subject to the use of good quality electronic states as input (e.g., the Hellman-Feynman theorem needs to be satisfied accurately). We investigate the relevance of the GCA for energy levels near avoided crossing regions using a system modeled on the EF 1Σ+g state of hydrogen. The results of numerical experiments on this system are very encouraging (80-90%) of the nonadiabatic effects is recovered. This numerical success awaits theoretical explanation.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/qua.560340852
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