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An improved MCSCF method
Author(s) -
Roothaan Clemens C. J.,
Detrich John,
Hopper Darrel G.
Publication year - 2009
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.560160811
Subject(s) - wave function , scheme (mathematics) , quadratic equation , convergence (economics) , exponential function , unitary state , field (mathematics) , symmetry (geometry) , mathematics , physics , quantum mechanics , mathematical analysis , pure mathematics , geometry , political science , economic growth , law , economics
An improved scheme for calculating multiconfiguration self‐consistent field wavefunctions has been developed. This scheme is powerful in its algebraic formulation and quadratic in its convergence behavior. Shell and wavefunction replacement operators are introduced to make equation manipulation more transparent and less tedious. The configuration state function coefficients as well as the orbital expansion coefficients are improved in each iteration by exponential unitary transformations. The symmetry properties of the wavefunctions are fully exploited. The present scheme should be convergent for a wider range of applications than currently available schemes.