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Computation of conical intersections by using perturbation techniques

Serrano-Andres, L; Merchan, M and Lindh, Roland LU (2005) In Journal of Chemical Physics 122(10). p.1-104107
Abstract
Multiconfigurational second-order perturbation theory, both in its single-state multiconfigurational second-order perturbation theory (CASPT2) and multistate (MS-CASPT2) formulations, is used to search for minima on the crossing seams between different potential energy hypersurfaces of electronic states in several molecular systems. The performance of the procedures is tested and discussed, focusing on the problem of the nonorthogonality of the single-state perturbative solutions. In different cases the obtained structures and energy differences are compared with available complete active space self-consistent field and multireference configuration interaction solutions. Calculations on different state crossings in LiF, formaldehyde, the... (More)
Multiconfigurational second-order perturbation theory, both in its single-state multiconfigurational second-order perturbation theory (CASPT2) and multistate (MS-CASPT2) formulations, is used to search for minima on the crossing seams between different potential energy hypersurfaces of electronic states in several molecular systems. The performance of the procedures is tested and discussed, focusing on the problem of the nonorthogonality of the single-state perturbative solutions. In different cases the obtained structures and energy differences are compared with available complete active space self-consistent field and multireference configuration interaction solutions. Calculations on different state crossings in LiF, formaldehyde, the ethene dimer, and the penta-2,4-dieniminium cation illustrate the discussions. Practical procedures to validate the CASPT2 solutions in polyatomic systems are explored, while it is shown that the application of the MS-CASPT2 procedure is not straightforward and requires a careful analysis of the stability of the results with the quality of the reference wave functions, that is, the size of the active space. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Chemical Physics
volume
122
issue
10
pages
1 - 104107
publisher
American Institute of Physics
external identifiers
  • pmid:15836309
  • wos:000228287500010
  • scopus:17544369194
ISSN
0021-9606
DOI
10.1063/1.1866096
language
English
LU publication?
yes
id
16b4383d-3cd5-481c-bc70-d5d0a45f0540 (old id 151936)
date added to LUP
2007-07-03 16:51:36
date last changed
2017-08-27 03:49:33
@article{16b4383d-3cd5-481c-bc70-d5d0a45f0540,
  abstract     = {Multiconfigurational second-order perturbation theory, both in its single-state multiconfigurational second-order perturbation theory (CASPT2) and multistate (MS-CASPT2) formulations, is used to search for minima on the crossing seams between different potential energy hypersurfaces of electronic states in several molecular systems. The performance of the procedures is tested and discussed, focusing on the problem of the nonorthogonality of the single-state perturbative solutions. In different cases the obtained structures and energy differences are compared with available complete active space self-consistent field and multireference configuration interaction solutions. Calculations on different state crossings in LiF, formaldehyde, the ethene dimer, and the penta-2,4-dieniminium cation illustrate the discussions. Practical procedures to validate the CASPT2 solutions in polyatomic systems are explored, while it is shown that the application of the MS-CASPT2 procedure is not straightforward and requires a careful analysis of the stability of the results with the quality of the reference wave functions, that is, the size of the active space.},
  author       = {Serrano-Andres, L and Merchan, M and Lindh, Roland},
  issn         = {0021-9606},
  language     = {eng},
  number       = {10},
  pages        = {1--104107},
  publisher    = {American Institute of Physics},
  series       = {Journal of Chemical Physics},
  title        = {Computation of conical intersections by using perturbation techniques},
  url          = {http://dx.doi.org/10.1063/1.1866096},
  volume       = {122},
  year         = {2005},
}