Adjustment of Ab Initio Potential Curves

A semiempirical method of adjusting ab initio diatomic molecule potential curves is described. The adjusted curve gives the exact result in the separated- and united-atom limits and also has correct asymptotic behavior in these limits. Different adjustment procedures are considered. At present, we favor the so-called ``pseudokinetic-energy'' adjustment procedure in which pseudokinetic energies are calculated from the virial formula. This procedure is applied to several ab initio potentials for He2 (1s2, 1s2s, 3Σu+).