INTERNUCLEAR DISTANCE AND REPULSIVE POTENTIAL BETWEEN NOBLE-GAS ATOMS - COMBINING RULES BASED ON REPULSIVE FORCE

Hartree-Fock calculations show that the internuclear distance R or repulsive potential U for a mixed pair AB of noble-gas atoms He, Ne, or Ar is very nearly the average of the same property for AA and BB, provided values for AA, BB, and AB are at the same repulsive force. For R(AB) greater than half the equilibrium internuclear distance the maximum errors in these combining rules are 2% for R(AB) and 3% for U(AB). The maximum error in the predicted function U(AB) (R) is 8%. Force-dependent dipole moment values for HeAr are predicted from moments for HeNe and NeAr with an accuracy of 6% or better. Consideration of force per unit area suggests why errors in R(AB) predictions are positive and are largest for HeAr. Nonoverlap of the interacting atoms is shown to be a nonessential feature of the distortion model on which the combining rules are based.