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Role of doubly excited states in calculations of optical activity
Author(s) -
Volosov Andrey
Publication year - 1989
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.560360404
Subject(s) - excited state , cndo/2 , configuration interaction , atomic physics , chemistry , ab initio quantum chemistry methods , ab initio , molecule , physics , organic chemistry
It is shown that doubly excited states play an important role in calculations of the optical activity of molecules with well‐conjugated electron systems, such as the DNA bases. In some significant cases it is necessary to include a large number of excited states in the configuration interaction ( CI ) to obtain a reliable, converging result. A new version of the CNDO/OPTIC method, which includes doubly excited states in the CI , is proposed. As an application, the electric transition moments in different pyrimidines are considered. The calculated results agree with experimental data and results obtained from ab initio calculations and INDO calculations using doubly excited states in the CI .