TY - JOUR
T1 - A quasi-complete active space self-consistent field method
AU - Nakano, Haruyuki
AU - Hirao, Kimihiko
N1 - Funding Information:
The present research was supported in part by the Grant-in-Aid for Scientific Research on Priority Areas `Molecular Physical Chemistry' from the Ministry of Education, Science, Sports and Culture of Japan.
Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 2000/1/28
Y1 - 2000/1/28
N2 - A multi-configuration self-consistent field method is proposed in which a quasi-complete active space, which is the product space of complete active spaces, is used as a variational space. The computational effort for wavefunctions is significantly reduced compared with the complete active space self-consistent field (CAS-SCF) method. Efficient formulae with segmented alpha and beta strings are derived. The scheme is tested on the spectroscopic constants and a potential energy curve of CO, the transition state barrier height of the reaction, H2CO→H2+CO, and the energy difference between trans- and cis-butadiene. The results are in good agreement with the corresponding CAS-SCF results.
AB - A multi-configuration self-consistent field method is proposed in which a quasi-complete active space, which is the product space of complete active spaces, is used as a variational space. The computational effort for wavefunctions is significantly reduced compared with the complete active space self-consistent field (CAS-SCF) method. Efficient formulae with segmented alpha and beta strings are derived. The scheme is tested on the spectroscopic constants and a potential energy curve of CO, the transition state barrier height of the reaction, H2CO→H2+CO, and the energy difference between trans- and cis-butadiene. The results are in good agreement with the corresponding CAS-SCF results.
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U2 - 10.1016/S0009-2614(99)01364-0
DO - 10.1016/S0009-2614(99)01364-0
M3 - Article
AN - SCOPUS:0002163015
VL - 317
SP - 90
EP - 96
JO - Chemical Physics Letters
JF - Chemical Physics Letters
SN - 0009-2614
IS - 1-2
ER -