The Valence Multipole Model, a New Pair Style

In this work we discuss our ongoing implementation of the Bond Valence Model into the molecular dynamics program Lammps. This pair style uses a fundamentally new form of energy decomposition to express the energy resulting from a particular geometric configuration. This decomposition is what we call the Valence Multipole Model. It separates the energy into isometric or total bonding, vector or bonding asymmetry, and quadrupole or ellipsoidal deformations, though the last will not be implemented in the initial release. Provided bond valence sums are satisfied to within 0.2 of the ideal for all atoms this model can provide accuracies of 5kJ/mol per unique atom, comparable to most quantum mechanical calculations.