George D. Purvis

A full coupled-cluster singles and doubles model: The inclusion of disconnected triples

The coupled-cluster singles and doubles model (CCSD) is derived algebraically, presenting the full set of equations for a general reference function explicitly in spin–orbital f...

Many‐body perturbation theory, coupled‐pair many‐electron theory, and the importance of quadruple excitations for the correlation problem

Abstract Many‐body (diagrammatic) perturbation theory ( MBPT ), coupled‐pair many‐electron theory ( CPMET ), and configuration interaction ( CI ) are investigated with particula...

Molecular Applications of Coupled Cluster and Many-Body Perturbation Methods

A series of molecular applications of many-body perturbation theory (MBPT) and the coupled-cluster doubles (CCD) model are described. Even though these methods have been availab...

The reduced linear equation method in coupled cluster theory.

A numerical procedure for efficiently solving large systems of linear equations is presented. The approach, termed the reduced linear equation (RLE) method, is illustrated by so...

ELECTRON CORRELATION IN LARGE MOLECULES WITH MANY‐BODY METHODS

Comparison of MBPT and coupled-cluster methods with full CI. Importance of triplet excitation and infinite summations

The potential energy curve for the <i>X</i>1Σ<i>g</i>+ state of Mg2 calculated with many-body perturbation theory

The ground state potential curve for the van der waals molecule, Mg2, is calculated by adding to the Hartree–Fock potential curve those many-body perturbation theory (MBPT) corr...