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Spin projected EHF method: Calculations for a four‐electron model system
Author(s) -
Mayer I.
Publication year - 1974
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.560080305
Subject(s) - hamiltonian (control theory) , atomic orbital , electronic correlation , electron , convergence (economics) , spin (aerodynamics) , physics , quantum mechanics , mathematics , thermodynamics , mathematical optimization , economics , economic growth
The spin projected extended Hartree‐Fock equations for successive optimization of the orbitals are derived for the four‐electron case and applied to butadiene in the PPP approximation. The method shows an excellent convergence and gives 91.4% of the correlation energy for the given model‐Hamiltonian.