An Error and Efficiency Analysis of Approximations to Møller−Plesset Perturbation Theory

We present a systematic study of the synergistic effects of popular approximations to Møller−Plesset perturbation theory through the second order (MP2). This work applies the density-fitting (DF) approximation for two-electron integrals, the dual-basis (DB) approximation for the Hartree−Fock reference, and the use of “heavy augmented” Dunning basis sets for basis set reduction, as well as combinations of these, to the S22 benchmark set of weakly bound dimers. For each approach, we report an error analysis as well as relative speedups for the 22 interaction energies in the set. Compared to the MP2/aug-cc-pVTZ level of theory, the DB-DF-MP2/heavy-aug-cc-pVTZ approach achieves an average speedup of 18 with a root-mean-square error of only 0.076 kcal mol −1 (2%).