Empirical potentials have long been utilized in classical molecular mechanics (MM) simulations of large atomistic systems containing thousands to millions of atoms.  More recently, physically motivated empirical potentials have been used to add the dispersion interaction to quantum chemistry calculations such as Hartree-Fock (HF) or semilocal density functional theory (DFT).  Here we extend this idea by introducing a series of physically motivated empirical potentials to correct for the various basis set incompleteness errors in HF and DFT.  We perform the counterpoise correction to evaluate the basis set superposition error, and symmetry-adapted perturbation theory is employed to decompose the remaining error into contributions including electrostatic, exchange repulsion, and induction.  This is followed by fitting empirical correction potentials to each separate contribution.  We outline the optimization procedure which uses an energy and force-matching framework, and apply the correction to improve the accuracy of ab initio molecular dynamics simulations of molecular clusters and small peptides.

Converging to the basis set limit using empirical correction potentials

243rd National Meeting (2012)

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