A modified definition of the zeroth-order Hamiltonian in multiconfigurational perturbation theory (CASPT2)
(2004) In Chemical Physics Letters 396(1-3). p.142-149- Abstract
- A new shifted zeroth-order Hamiltonian is presented, which will be used in second-order multiconfigurational perturbation theory (CASPT2). The new approximation corrects for the systematic error of the original formulation, which led to an relative overestimate of the correlation energy for open shell system, resulting in too small dissociation and excitation energies. Errors in the D, values for 49 diatomic molecules have been reduced with more than 50%. Calculations on excited states of the N-2 and benzene molecules give a similar improvement. (C) 2004 Elsevier B.V. All rights reserved.
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/139596
- author
- Ghigo, Giovanni LU ; Roos, Björn LU and Malmqvist, Per-Åke LU
- organization
- publishing date
- 2004
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Chemical Physics Letters
- volume
- 396
- issue
- 1-3
- pages
- 142 - 149
- publisher
- Elsevier
- external identifiers
-
- wos:000223972300026
- scopus:8344289249
- ISSN
- 0009-2614
- DOI
- 10.1016/j.cplett.2004.08.032
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Theoretical Chemistry (S) (011001039)
- id
- a7d216d2-c45c-4c67-9aa1-d74336580fe8 (old id 139596)
- date added to LUP
- 2016-04-01 16:50:48
- date last changed
- 2023-04-08 12:09:58
@article{a7d216d2-c45c-4c67-9aa1-d74336580fe8, abstract = {{A new shifted zeroth-order Hamiltonian is presented, which will be used in second-order multiconfigurational perturbation theory (CASPT2). The new approximation corrects for the systematic error of the original formulation, which led to an relative overestimate of the correlation energy for open shell system, resulting in too small dissociation and excitation energies. Errors in the D, values for 49 diatomic molecules have been reduced with more than 50%. Calculations on excited states of the N-2 and benzene molecules give a similar improvement. (C) 2004 Elsevier B.V. All rights reserved.}}, author = {{Ghigo, Giovanni and Roos, Björn and Malmqvist, Per-Åke}}, issn = {{0009-2614}}, language = {{eng}}, number = {{1-3}}, pages = {{142--149}}, publisher = {{Elsevier}}, series = {{Chemical Physics Letters}}, title = {{A modified definition of the zeroth-order Hamiltonian in multiconfigurational perturbation theory (CASPT2)}}, url = {{http://dx.doi.org/10.1016/j.cplett.2004.08.032}}, doi = {{10.1016/j.cplett.2004.08.032}}, volume = {{396}}, year = {{2004}}, }