MULTIPROPERTY DETERMINATION OF A NEW N2-AR INTERMOLECULAR INTERACTION POTENTIAL-ENERGY SURFACE

A new multiproperty potential energy surface for the N2-Ar intermolecular interaction is reported. The present determination is based upon molecular beam total differential and integral scattering data, taken together with the temperature dependence of the interaction second virial coefficient, transport properties, transport property field effects, and relaxation phenomena, such as pressure broadening of the depolarized Rayleigh line and longitudinal nuclear spin relaxation. The primary fit has been made to the beam scattering and virial data, and refinements to the potential parameters thus determined have been made by employing the data available for the gas phase transport and relaxation phenomena. The potential energy surface employed is an empirical Morse-Morse-spline-van der Waals form, in which the potential parameters depend upon the angle between the N2 figure axis and the line joining the centers of mass of N2 and Ar. No N2 stretching dependence has been included in the present determination. Comparison is made between the present potential energy surface and two other previously published N2-Ar potential energy surfaces. The present potential energy surface provides the best overall agreement for all available gas phase data for N2-Ar mixtures, and can thus be recommended for calculations of all properties of such mixtures that depend upon the intermolecular interaction.