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A study of the Colle–Salvetti formula for the calculation of the correlation energy
Author(s) -
Flocco Maria,
Gao XueQin,
Massa Lou
Publication year - 1990
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.560382422
Subject(s) - ansatz , electronic correlation , chemistry , formalism (music) , beryllium , ion , atomic physics , computational chemistry , electron , quantum mechanics , physics , art , musical , organic chemistry , visual arts
The formalism of Colle and Salvetti for the calculation of the correlation energy of electronic systems has proven to be highly successful in a wide variety of applications. Several authors have applied the method and analyzed its usefulness. The Colle and Salvetti ansatz for the correlation energy is We test the limits of validity for expression (2) by applying it to the series of ions isoelectronic with helium, (two‐electron case) and beryllium, (four‐electron case). We find that the approximation breaks down for sufficiently high Z . We also compare the results given by Eqs. (1) and (2). We find that although both expressions give the same result for the neutral He atom, in general they do not.