Theoretical Chemistry Accounts

, Volume 127, Issue 4, pp 311–325

The role of orbital transformations in coupled-pair functionals

Regular Article

DOI: 10.1007/s00214-009-0719-5

Cite this article as:
Kollmar, C. & Heßelmann, A. Theor Chem Acc (2010) 127: 311. doi:10.1007/s00214-009-0719-5

Abstract

The replacement of single excitations by orbital transformations in coupled-pair functionals derived from a single double configuration interaction approach is discussed. It is demonstrated that this modification leads to considerably improved density matrices and better agreement with results from coupled cluster singles doubles calculations taken as a reference. A comparison between the variationally optimized orbitals and the Brueckner orbitals shows that these two sets of orbitals are different.

Keywords

Configuration interactionCoupled-pair functionalOrbital optimizationBrueckner orbitalsSize extensivity

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Lehrstuhl für Theoretische ChemieUniversität BonnBonnGermany
  2. 2.Lehrstuhl für Theoretische ChemieUniversität ErlangenErlangenGermany