Efficient and accurate electron propagator methods and algorithms

Abstract

Recent developments in electron propagator methods that employ the quasiparticle approximation can facilitate calculations on molecules of unprecedented size. Reductions of arithmetic and storage requirements are considered. New and reliable approximations that offer a better compromise of accuracy and feasibility are proposed. Transition operator orbitals, in combination with the second-order self-energy, provide reliable predictions for valence and core electron binding energies with algorithms that are comparable in efficiency to their counterparts that employ ordinary Hartree-Fock orbitals. Quasiparticle virtual orbitals enable accurate evaluation of third-order self-energy contributions, while significantly reducing storage and arithmetic requirements. Algorithms that employ the resolution-of-the-identity approach to the evaluation of electron repulsion integrals require less memory but retain the accuracy of ordinary calculations. Numerical tests confirm the promise of these new approaches. © 2010 Springer Science+Business Media B.V.