Corresponding States Principle for the Alkaline Earth Dimers and the van der Waals Potential of Ba2

A simple method based on the corresponding states principle and the Tang-Toennies potential model is used for the determination of the ground state van der Waals potential of barium dimer. The potential energy curve calculated from the theoretical dispersion coefficients and the experimental vibrational frequency is comparable to other quantum chemical calculations. To assess its validity, the same method is used to calculate the potential of the strontium dimer, for which there are many theoretical and experimental determinations. A comparison with experimental measurements suggests that the present method is highly accurate. The potentials of five alkaline earth dimers are compared. The potentials of Mg-2, Ca-2, Sr-2, and Ba-2 are shown to be nearly conformal with each other. The potential of Be-2 has a different shape.