Direct measurements of the intermolecular interaction potentials from the extended principle of corresponding states for O-2-He and O-2-Ar

An inversion procedure is used to obtain from extended principle of corresp onding states, the interaction potentials over a range of reduced temperatu re extending from 1 to 100. These directly measured potentials for O-2-He a nd O-2-Ar agree excellently with the ESMSV (Exponential-Spline-Morse-Spline -Van der Waals)-type independently known potential. This technique also lar gely eliminates the need for the unsatisfactory trial and error methods whi ch have been used to obtain potential energy functions from thermo-physical data. These accurate inverted potentials can be used to the orientation-av eraged viscosity collision integrals and the dimensionless ratios which are essential to calculate other transport properties.