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Using full‐CI algorithms in Bethe‐Goldstone‐type expansions of the correlation energy
Author(s) -
Povill Àngels,
Rubio Jaime
Publication year - 1997
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/(sici)1097-461x(1997)61:1<35::aid-qua4>3.0.co;2-5
Subject(s) - atomic orbital , goldstone , convergence (economics) , basis set , electronic correlation , basis (linear algebra) , electron , set (abstract data type) , physics , spin (aerodynamics) , statistical physics , energy (signal processing) , quantum mechanics , algorithm , molecule , mathematics , computer science , geometry , geodesy , economic growth , economics , thermodynamics , programming language , geography
In the early 1960s, Nesbet proposed to develop correlation energy in terms of two‐, three‐, four‐, etc., electron contributions. This expansion was, in principle, applicable to a large number of electrons without a size‐extensivity error. The now available full‐CI algorithms may be used to obtain those expansions in terms of either occupied spin—orbitals or, more efficiently, in terms of sets of occupied or virtual molecular orbitals. Tests on the NH 3 molecule with a DZP basis‐set problem show the slow convergence of this approach. © 1997 John Wiley & Sons, Inc.