TOWARDS PHASE TRANSFERABLE POTENTIAL FUNCTIONS - METHODOLOGY AND APPLICATION TO NITROGEN

We describe a generalizable approach to the development of phase trans ferable effective intermolecular potentials and apply the method to th e study of N-2 The method is based on a polarizable shell model descri ption of the isolated molecule and uses experimental data to establish the parameters. Consideration of the Ne dimer shows this to be a conc eptual advance over point polarizability descriptions of atomic intera ction. Our parametrization of N-2 accurately describes not only the mo lecule's electrostatic field (i.e., a practical representation of the molecular charge distribution) but also its response to electrical and mechanical stress (polarization and deformation). The purely intermol ecular terms in our potential reflect shell-shell interactions. These are parametrized by fitting properties of the low temperature solid ph ase of nitrogen. We derive a phase transferable potential able to acco unt for the second virial coefficient of the gas phase, the pressure i nduced phase transition between nitrogen's cubic and tetragonal phrase s, and a wide range of liquid properties (pair distribution function, heat of vaporization, self-diffusion coefficient and dielectric consta nt). (C) 1995 American Institute of Physics.