Collect. Czech. Chem. Commun. 2005, 70, 1109-1132

Time-Independent Coupled-Cluster Theory of the Polarization Propagator

Robert Moszynski, Piotr S. Żuchowski and Bogumił Jeziorski*

Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland


A novel, time-independent formulation of the coupled-cluster theory of the polarization propagator is presented. This formulation, unlike the equation-of-motion coupled-cluster approach, is fully size-extensive and, unlike the conventional time-dependent coupled-cluster method, is manifestly Hermitian, which guarantees that the polarization propagator is always real for purely imaginary frequencies and that the resulting polarizabilities exhibit time-reversal symmetry (are even functions of frequency) for purely real or purely imaginary perturbations. This new formulation is used to derive compact expressions for the three leading terms in the Møller-Plesset expansion for the polarization propagator. The true and apparent correlation contributions to the second-order term are analyzed and separated at the operator level. Explicit equations for the polarization propagator at the non-perturbative, singles and doubles level (CCSD) are presented.

Keywords: Linear-response theory; Polarization propagator; Coupled clusters; CCSD; Møller-Plesset expansion; Wave functions; Quantum chemistry.

References: 58 live references.