ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
The accuracy of geometries, vibrational frequencies and dipole moments of stationary points on excited state potential energy surfaces is assessed for three single reference excited state theories—configuration interaction (CIS), a perturbative doubles correlation correction to CIS, termed CIS(D), and equation-of-motion coupled cluster theory with single and double substitutions (EOM-CCSD). Two groups of systems are studied: the diatomic molecules H2, BH, BF, C2, CO, and N2; and the lowest singlet excited states of ammonia, formaldehyde and acetylene. The calculations demonstrate that CIS systematically underestimates bond lengths and overestimates frequencies and dipole moments, a pattern often associated with the Hartree–Fock method for ground states. CIS(D) fails to provide a systematic improvement to CIS for all geometries and frequencies, often overestimating correlation corrections. EOM-CCSD, by contrast, performs significantly better than CIS for all properties considered. © 1995 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.469601
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