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CASSCF optimization problem for a group of excited states
Author(s) -
Khait Yu. G.,
Panin A. I.
Publication year - 1992
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.560430609
Subject(s) - excited state , atomic orbital , complete active space , basis set , ground state , group (periodic table) , energy minimization , parametrization (atmospheric modeling) , set (abstract data type) , chemistry , quantum chemistry , domain (mathematical analysis) , space (punctuation) , basis (linear algebra) , quantum mechanics , atomic physics , physics , computer science , mathematics , molecule , mathematical analysis , geometry , supramolecular chemistry , operating system , programming language , radiative transfer , electron
A second‐order version of the CASSCF approach to the optimization problem for a single (ground or excited) state and a group of excited states (involving, if necessary, also the ground state) is proposed. In contrast to the already existing methods, in the frameworks of our approach, there arises no need in completing the set of states to be optimized to the full basis set of configuration function space. Generation of secondary orbitals in the course of orbital optimization is also not required. All necessary integral transformations are performed only with active orbitals. These certainly attractive features of our approach appear due to employing the Gauss parametrization of average electronic energy domain, which is nonstandard in quantum chemistry. © 1992 John Wiley & Sons, Inc.