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The restricted active space followed by second-order perturbation theory method: Theory and application to the study of CuO(2) and Cu(2)O(2) systems.

Malmqvist, Per-Åke LU ; Pierloot, Kristine; Shahi, Abdul Rehaman Moughal; Cramer, Christopher J and Gagliardi, Laura (2008) In Journal of Chemical Physics 128(20).
Abstract
A multireference second-order perturbation theory using a restricted active space self-consistent field wave function as reference (RASPT2/RASSCF) is described. This model is particularly effective for cases where a chemical system requires a balanced orbital active space that is too large to be addressed by the complete active space self-consistent field model with or without second-order perturbation theory (CASPT2 or CASSCF, respectively). Rather than permitting all possible electronic configurations of the electrons in the active space to appear in the reference wave function, certain orbitals are sequestered into two subspaces that permit a maximum number of occupations or holes, respectively, in any given configuration, thereby... (More)
A multireference second-order perturbation theory using a restricted active space self-consistent field wave function as reference (RASPT2/RASSCF) is described. This model is particularly effective for cases where a chemical system requires a balanced orbital active space that is too large to be addressed by the complete active space self-consistent field model with or without second-order perturbation theory (CASPT2 or CASSCF, respectively). Rather than permitting all possible electronic configurations of the electrons in the active space to appear in the reference wave function, certain orbitals are sequestered into two subspaces that permit a maximum number of occupations or holes, respectively, in any given configuration, thereby reducing the total number of possible configurations. Subsequent second-order perturbation theory captures additional dynamical correlation effects. Applications of the theory to the electronic structure of complexes involved in the activation of molecular oxygen by mono- and binuclear copper complexes are presented. In the mononuclear case, RASPT2 and CASPT2 provide very similar results. In the binuclear cases, however, only RASPT2 proves quantitatively useful, owing to the very large size of the necessary active space. (Less)
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organization
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Contribution to journal
publication status
published
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in
Journal of Chemical Physics
volume
128
issue
20
publisher
American Institute of Physics
external identifiers
  • wos:000256304200013
  • pmid:18513012
  • scopus:44649111460
ISSN
0021-9606
DOI
10.1063/1.2920188
language
English
LU publication?
yes
id
4154ca77-c513-4160-aeb8-5e593ef7bd49 (old id 1169408)
date added to LUP
2009-03-09 11:58:57
date last changed
2017-11-12 03:32:27
@article{4154ca77-c513-4160-aeb8-5e593ef7bd49,
  abstract     = {A multireference second-order perturbation theory using a restricted active space self-consistent field wave function as reference (RASPT2/RASSCF) is described. This model is particularly effective for cases where a chemical system requires a balanced orbital active space that is too large to be addressed by the complete active space self-consistent field model with or without second-order perturbation theory (CASPT2 or CASSCF, respectively). Rather than permitting all possible electronic configurations of the electrons in the active space to appear in the reference wave function, certain orbitals are sequestered into two subspaces that permit a maximum number of occupations or holes, respectively, in any given configuration, thereby reducing the total number of possible configurations. Subsequent second-order perturbation theory captures additional dynamical correlation effects. Applications of the theory to the electronic structure of complexes involved in the activation of molecular oxygen by mono- and binuclear copper complexes are presented. In the mononuclear case, RASPT2 and CASPT2 provide very similar results. In the binuclear cases, however, only RASPT2 proves quantitatively useful, owing to the very large size of the necessary active space.},
  articleno    = {204109},
  author       = {Malmqvist, Per-Åke and Pierloot, Kristine and Shahi, Abdul Rehaman Moughal and Cramer, Christopher J and Gagliardi, Laura},
  issn         = {0021-9606},
  language     = {eng},
  number       = {20},
  publisher    = {American Institute of Physics},
  series       = {Journal of Chemical Physics},
  title        = {The restricted active space followed by second-order perturbation theory method: Theory and application to the study of CuO(2) and Cu(2)O(2) systems.},
  url          = {http://dx.doi.org/10.1063/1.2920188},
  volume       = {128},
  year         = {2008},
}