Title: Bivariational coupled-cluster approach for the study of static electronic<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">properties</mml:mi></mml:mrow><mml:mrow><mml:mo>/</mml:mo><mml:mi mathvariant="normal">e</mml:mi><mml:mi mathvariant="normal">m</mml:mi><mml:mi mathvariant="normal">p</mml:mi><mml:mi mathvariant="normal">h</mml:mi><mml:mo>></mml:mo><mml:mn /></mml:mrow></mml:msup></mml:mrow></mml:math>
Abstract: A bivariational coupled-cluster method is advocated for the calculation of static electronic properties for closed-shell atomic and molecular systems. The proposed method uses a perturbed form of the Hamiltonian H(\ensuremath{\lambda}) which includes the field with which the system interacts, giving rise to the response in various orders. Higher-order properties can be calculated without the use of excited states. A novel linked energy functional ${\mathrm{scrJ}}_{H}^{\ensuremath{\lambda}}$[T,T''] is used with two different types of cluster parameters T(\ensuremath{\lambda}) and T''(\ensuremath{\lambda}), each of which is a power series in \ensuremath{\lambda}. Unlike the Euler energy functional proposed in one of our earlier works, this functional is a terminating series in cluster parameters. It is shown that the set of stationarity equations of ${\mathrm{scrJ}}_{H}^{\ensuremath{\lambda}}$ with respect to arbitrary variation of the cluster parameters of T(\ensuremath{\lambda}) and T''(\ensuremath{\lambda}) corresponding to any power of \ensuremath{\lambda} is the same for certain conditions and furnishes all the relevant values of cluster parameters. The equations are derived for calculating static properties to any order with these stationary optimum values.
Publication Year: 1986
Publication Date: 1986-10-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 34
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