Attenuating Away the Errors in Inter- and Intramolecular Interactions from Second-Order Møller-Plesset Calculations in the Small Aug-cc-pVDZ Basis Set.
Second-order Møller-Plesset perturbation theory (MP2) treats electron correlation at low computational cost, but suffers from basis set superposition error (BSSE) and fundamental inaccuracies in long-range contributions. The cost differential between complete basis set (CBS) and small basis MP2 restricts system sizes where BSSE can be removed. Range-separation of MP2 could yield more tractable and/or accurate forms for short- and long-range correlation. Retaining only short-range contributions proves to be effective for MP2 in the small aug-cc-pVDZ (aDZ) basis. Using one range-separation parameter, superior behavior is obtained versus both MP2/aDZ and MP2/CBS for inter- and intramolecular test sets. Attenuation of the long-range helps to cancel both BSSE and intrinsic MP2 errors. Direct scaling of the MP2 correlation energy proves useful as well. The resulting SMP2/aDZ, MP2(erfc, aDZ), and MP2(terfc, aDZ) methods perform far better than MP2/aDZ across systems with hydrogen-bonding, dispersion, and mixed interactions at a fraction of MP2/CBS computational cost.
Department of Chemistry, University of California, Berkeley, California 94720, United States.|Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
Matthew
M
Goldey
Department of Chemistry, University of California, Berkeley, California 94720, United States.|Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
Martin
M
Head-Gordon
conformational energies; dispersion; hydrogen-bonding; local correlation methods; nonbonded interactions