Calculation of Dissociation Energies Using Many - Body Perturbation Theory

A major task for theoretical chemists is the development of methods to predict energy differences with chemical accuracy. Most quantum chemists agree that accurate prediction of relative energies requires application of theories that include electron correlation effects, effects not treated in self-consistent-field (SCF) calculations [1-4]. Estimates of molecular correlation energy have been obtained by using the method of configuration interaction to improve the wavefunction obtained from an ab initio SCF calculation. Recently, however, theoretical techniques based upon the linked-diagram theorem have been extended to molecular applications [1,2, 4], and these methods provide an alternative approach to the correlation problem. Several comparisons of the various theoretical methods have appeared [1,2,4]. This report describes the application of many-body perturbation theory (MBPT) to predict the dissociation energies for a series of reactions that occur in