ANGLE AND BOND-LENGTH DEPENDENT C-6 COEFFICIENTS FOR H-2 INTERACTING WITH H, LI, BE AND RARE-GAS ATOMS

Accurate new C6 dispersion energy coefficients, and their dependence on the diatom orientation and bond length, are calculated for molecular hydrogen interacting with an atom of H, Li, Be, He, Ne, Ar, Kr or Xe. They are generated from accurate ab initio pseudo dipole oscillator strength distributions (DOSD) for H-2, H, He and Be, and reliable semiempirical ones for Li, Ne, Ar, Kr and Xe. Compact power series expansions for the diatom bond-length dependence of these coefficients, suitable for incorporation into representations of full potential energy surfaces for these systems, are determined and assessed.