Laplace-transformed diagonal Dyson correction to quasiparticle energies in periodic systems

A method to self-consistently evaluate quasiparticle energies and pole strengths of periodic systems within diagonal approximation for solving Dyson's equation, was described. The method was found to be based on the Laplace transform of second-order MØller-Plesset perturbation (MP2) theory kernel in atomic basis formulation. MP2 accounts for long-range van der Waals dispersion interactions and it is self-interaction free, which makes it accurate and reliable, albeit substantially more expensive computationally. The interchain interactions affect the band gap in a sizeable manner such that MP2 band gap of two interacting trans-polyacetylene chains is reduced to 0.5 eV.