Chemistry, Ames Laboratory
Journal or Book Title
Journal of Chemical Physics
A method for calculating the dispersion energy between molecules modeled with the general effective fragment potential (EFP2) method and those modeled using a full quantum mechanics (QM) method, e.g., Hartree-Fock (HF) or second-order perturbation theory, is presented. C6dispersion coefficients are calculated for pairs of orbitals using dynamic polarizabilities from the EFP2 portion, and dipole integrals and orbital energies from the QM portion of the system. Dividing by the sixth power of the distance between localized molecular orbital centroids yields the first term in the commonly employed London series expansion. A C 8 term is estimated from the C 6 term to achieve closer agreement with symmetry adapted perturbation theory values. Two damping functions for the dispersion energy are evaluated. By using terms that are already computed during an ordinary HF or EFP2 calculation, the new method enables accurate and extremely rapid evaluation of the dispersioninteraction between EFP2 and QM molecules.
Copyright 2012 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
American Institute of Physics
Smith, Quentin Anthony; Ruedenberg, Klaus; Gordon, Mark S.; and Slipchenko, Lyudmila V., "The Dispersion Interaction between Quantum Mechanics and Effective Fragment Potential Molecules" (2012). Chemistry Publications. 613.