Third-order many-body perturbation theory in the Moller-Plesset partitioning applied to an infinite alternating hydrogen chain

Abstract

Many-body perturbation theory up to third order in the Moller-Plesset partitioning has been used to calculate the correlation energy and the threshold ionisation potential of an infinite alternating hydrogen chain. Both second- and third-order contributions to the correlation energy tend to reduce the Peierls distortion observed in the Hartree-Fock picture. For the quasiparticle energies the third-order correction is appreciable in absolute value compared with the second-order correction. The band widths and the fundamental gap in the quasiparticle picture are also strongly influenced by the third-order perturbation contributions.