An alternative approximation to state-specific multireference second-order Brillouin-Wigner perturbation theory: size-extensivity correction

Aksu H.

THEORETICAL CHEMISTRY ACCOUNTS, vol.132, no.3, 2013 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 132 Issue: 3
  • Publication Date: 2013
  • Doi Number: 10.1007/s00214-012-1325-5
  • Journal Name: THEORETICAL CHEMISTRY ACCOUNTS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Çanakkale Onsekiz Mart University Affiliated: No

Abstract

State-specific, multireference, second order, Brillouin-Wigner perturbation theory is examined provided that providing a size-extensive correction to the electron correlation problem for systems that demand the use of a multireference function. We derived the renormalization term. An important aspect of this renormalization term is to cancel the non-physical terms. The computer implementations are made for bond breaking process in the ground states of the diatomic hydride using the two configuration state functions. We have achieved improved results. The results are compared with the rigorously size-extensive methods such as, MOller-Plesset perturbation theory, that is, MP2, full configuration interaction and allied methods using the same basis sets.