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Exchange perturbation theory calculations of the interaction energy between two ground‐state hydrogen atoms
Author(s) -
Adams William H.,
Clayton Meredith M.,
Polymeropoulos E. E.
Publication year - 1984
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560260837
Subject(s) - perturbation theory (quantum mechanics) , ground state , atomic orbital , perturbation (astronomy) , basis set , atomic physics , interaction energy , exchange interaction , configuration interaction , series (stratigraphy) , physics , electron , quantum mechanics , chemistry , molecule , paleontology , ferromagnetism , biology
We have carried out a series of calculations of the interaction energy between two hydrogen atoms in their ground states, using three kinds of exchange perturbation theory. One objective was to test the accuracy that could be achieved with these perturbation methods. A second was to see if the results were consistent with those for H 2 + . The perturbation equations were solved within the configuration interaction approximation, using 226 partially symmetry‐contracted, two‐electron basis functions. The set of Slater‐type basis orbitals was chosen so that we could approximate within two percent the most accurate calculated interaction energies. We report here our second‐order energies at a series of nuclear separations and compare them to the best values that have been published. Some of the published values are inaccurate. We also present the percent errors in the interaction energies approximated by summing through second and third orders. We discuss some general implications of our results.