QUADRUPOLE POLARIZATION IN SIMULATIONS OF IONIC SYSTEMS - APPLICATIONTO AGCL

A method which allows for the effects of dipole and quadrupole polariz ations on the interparticle interactions in molecular dynamics simulat ions is described. Multipole induction by both Coulombic and short-ran ge interactions is included. The validity of a description of the inte ractions in condensed ionic systems with pair potentials supplemented with a description of polarization effects is assessed, and the implic ations for reliably parameterizing such a model are discussed. The rol e of cation quadrupole polarization is explored in simulations of soli d and liquid AgCl. The effect is to substantially improve the agreemen t with experiment of properties such as phonon dispersion and liquid s tructure relative to calculations with a simple pair potential.