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Spin‐projected EHF method. IV. Comparison of potential curves given by different one‐electron methods
Author(s) -
Mayer I.
Publication year - 1978
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.560140104
Subject(s) - spurious relationship , ultra high frequency , wave function , gaussian , ab initio , maxima and minima , electron , physics , spin (aerodynamics) , realization (probability) , computational physics , chemistry , atomic physics , quantum mechanics , mathematical analysis , mathematics , computer science , telecommunications , statistics , thermodynamics
Some aspects of the computer realization of the spin‐projected extended Hartree–Fock ( EHF ) method at the ab initio level are briefly discussed for the algorithm of solution developed in the previous papers of this series. Calculations have been performed for the BH molecule by using a small basis of contracted Gaussian lobes with the purpose of comparing the potential curves given by the different one‐electron methods RHF , UHF , UHF with subsequent spin projection, and EHF . It is concluded that the UHF and, in particular, the EHF methods give a qualitatively correct shape of the potential curve; the RHF method shows the known incorrect dissociation behavior while the potential curve obtained by subsequent spin projection of the UHF wave function exhibits spurious extrema at intermediate internuclear separations.