MULTIPROPERTY DETERMINATION OF A NEW N2-AR INTERMOLECULAR INTERACTIONPOTENTIAL-ENERGY SURFACE

A new multiproperty potential energy surface for the N2-Ar intermolecu lar interaction is reported. The present determination is based upon m olecular beam total differential and integral scattering data, taken t ogether with the temperature dependence of the interaction second viri al coefficient, transport properties, transport property field effects , and relaxation phenomena, such as pressure broadening of the depolar ized Rayleigh line and longitudinal nuclear spin relaxation. The prima ry fit has been made to the beam scattering and virial data, and refin ements to the potential parameters thus determined have been made by e mploying the data available for the gas phase transport and relaxation phenomena. The potential energy surface employed is an empirical Mors e-Morse-spline-van der Waals form, in which the potential parameters d epend upon the angle between the N2 figure axis and the line joining t he 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 pr ovides the best overall agreement for all available gas phase data for N2-Ar mixtures, and can thus be recommended for calculations of all p roperties of such mixtures that depend upon the intermolecular interac tion.