Estimation of second virial coefficients for rare gases in thermodynamic views

Using the Gaussian 2003 software and MP2/ 6–311 ++ G** method for He: He, Ne:Ne and MP2/6-31G method for Ar: Ar, Kr: Kr and HF/STO-3G method for Xe: Xe, the optimized interaction energies between two like atoms of rare gases (He, Ne, Ar, Kr and Xe) as a function of the distances between the centers of two considered atoms were evaluated and the results were interpreted according to the Lennard – Jones equation . In addition, the second virial coefficient of each rare gas was calculated upon the appropriate equations of statistical thermodynamics. The resultent coefficients were comparable with those are available in the literature.