Improved Algorithms for Renormalized Electron Propagator Calculations

摘要

A new algorithm has been developed for renormalized electron propagator methods that are appropriate for shakeup final states such as the algebraic diagrammatic construction in third order, the two-particle, one-hole Tamm-Dancoff approximation and the nondiagonal, renormalized, second-order approximation. All contractions are performed with transformed electron repulsion integrals that are stored on disk. It is formulated for closed-shell ground states and employs spin and point-group symmetry. Contributions from transformed integrals with four virtual indices may be computed by a direct algorithm, where integrals in the atomic basis are recalculated as needed. A representative application to the ionization energies of trans-1,3-butadiene is discussed.