Exact and approximate adiabatic connection formulae for the correlation energy in multireference ground and excited states.
J Chem Phys
; 149(20): 204101, 2018 Nov 28.
Article
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| MEDLINE
| ID: mdl-30501241
ABSTRACT
Recently it has been shown how to employ the adiabatic connection (AC) formalism to obtain correlation energy for multireference wavefunctions [K. Pernal, Phys. Rev. Lett. 120, 013001 (2018)]. Approximations to the exact AC formulation have been based on assuming that a one-electron reduced density matrix is constant along the AC path and by employing the extended random phase approximation. In this paper, the importance of these approximations is examined by comparing approximate AC integrands with their exact counterparts obtained for the hydrogen molecule in its ground and excited states. Encouraging results obtained for H2 indicate that AC is a viable and promising approach to a correlation energy problem not only for ground but also for excited states of electronic systems.
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01-internacional
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MEDLINE
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En
Revista:
J Chem Phys
Año:
2018
Tipo del documento:
Article
País de afiliación:
Polonia