A simple implementation of third-order perturbation theory applied to a multireference zero-order wavefunction is presented. Two different partitions of the Hamiltonian (Møller-Plesset baricentric and Epstein-Nesbet) are considered. Two test cases, CH2 and N2, are examined. The third-order results are shown to be in good agreement in either partition and are generally an improvement with respect to the second-order results. The phenomenon of intruder states, absent in Epstein-Nesbet, appears to be magnified in the Møller-Plesset partition.

Multireference perturbation configuration interaction. V. Third-order energy contributions in the Moller-Plesset and Epstein-Nesbet partitions.

ANGELI, Celestino;CIMIRAGLIA, Renzo
2002

Abstract

A simple implementation of third-order perturbation theory applied to a multireference zero-order wavefunction is presented. Two different partitions of the Hamiltonian (Møller-Plesset baricentric and Epstein-Nesbet) are considered. Two test cases, CH2 and N2, are examined. The third-order results are shown to be in good agreement in either partition and are generally an improvement with respect to the second-order results. The phenomenon of intruder states, absent in Epstein-Nesbet, appears to be magnified in the Møller-Plesset partition.
2002
Angeli, Celestino; Cimiraglia, Renzo
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/1199172
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 65
  • ???jsp.display-item.citation.isi??? 66
social impact