title: Explicitly correlated plane waves: accelerating convergence in periodic wavefunction expansions.
abstract: We present an investigation into the use of an explicitly correlated plane wave basis for periodic wavefunction expansions at the level of second-order Møller-Plesset (MP2) perturbation theory. The convergence of the electronic correlation energy with respect to the one-electron basis set is investigated and compared to conventional MP2 theory in a finite homogeneous electron gas model. In addition to the widely used Slater-type geminal correlation factor, we also derive and investigate a novel correlation factor that we term Yukawa-Coulomb. The Yukawa-Coulomb correlation factor is motivated by analytic results for two electrons in a box and allows for a further improved convergence of the correlation energies with respect to the employed basis set. We find the combination of the infinitely delocalized plane waves and local short-ranged geminals provides a complementary, and rapidly convergent basis for the description of periodic wavefunctions. We hope that this approach will expand the scope of discrete wavefunction expansions in periodic systems.
authors.affiliation: Chemistry Department, University of Cambridge, Lensfield Road, Cambridge CB2 1EQ, United Kingdom.
authors.forename: Andreas
authors.initials: A
authors.lastname: Grüneis
authors.forename: James J
authors.initials: JJ
authors.lastname: Shepherd
authors.forename: Ali
authors.initials: A
authors.lastname: Alavi
authors.forename: David P
authors.initials: DP
authors.lastname: Tew
authors.forename: George H
authors.initials: GH
authors.lastname: Booth