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Collectivity, shell openness indices, and complexity measures of multiconfigurational states: Computations within full CI scheme
Author(s) -
Luzanov A. V.,
Zhikol O. A.
Publication year - 2005
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.20511
Subject(s) - wave function , computation , electron , open shell , quantum mechanics , unpaired electron , configuration interaction , invariant (physics) , physics , chemistry , statistical physics , atomic physics , mathematics , molecule , algorithm
It is shown that the multiconfigurational character of the N ‐electron wave function can be treated by a new quantitative index, N κ eff , computed as a special matrix invariant of the full wave function. Along with N κ eff , a simpler index N av effis given due to the Kutzelnigg and Smith open‐shell theory. The indices are compared with an effective number of unpaired electrons introduced by Takatsuki, Fueno, and Yamaguchi. Full configuration interaction (FCI) computations on such quantities realized in the present work for atoms and dissociation reactions lead to the conclusion that all indices give a qualitatively similar picture. It is stressed that N κ effas a more complicated quantity reflects a global complexity of the electronic state, while other indices represent the electron structure peculiarities only at the one‐electron level. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005