Long-range electrostatic interactions in hybrid quantum and molecular mechanical dynamics using a lattice summation approach.
A method based on a lattice summation technique for treating long-range electrostatic interactions in hybrid quantum mechanics/molecular mechanics simulations is presented in this article. The quantum subsystem is studied at the semiempirical level, whereas the solvent is described by a two-body potential of molecular mechanics. Molecular dynamics simulations of a (quantum) chloride ion in (classical) water have been performed to test this technique. It is observed that the application of the lattice summations to solvent-solvent interactions as well as on solute-solvent ones has a significant effect on solvation energy and diffusion coefficient. Moreover, two schemes for the computation of the long-range contribution to the electrostatic interaction energy are investigated. The first one replaces the exact charge distribution of the quantum solute by a Mulliken charge distribution. The long-range electrostatic interactions are then calculated for this charge distribution that interacts with the solvent molecule charges. The second one is more accurate and involves a modified Fock operator containing long-range electron-charge interactions. It is shown here that both schemes lead to similar results, the method using Mulliken charges for the evaluation of long-range interactions being, however, much more computationally efficient.
Dehez
François
F
Unité Mixte de Recherche, Centre National de la Recherche Scientifique-Université Henri Poincaré (CNRS-UHP) 7565, Institut Nancéien de Chimie Moléculaire, Université Henri Poincaré-Nancy I, BP 239, Vandoeuvre-lès-Nancy 54506, France.
Martins-Costa
Marília T C
MT
Rinaldi
Daniel
D
Millot
Claude
C