Towards universal potentials for (H2)2 and isotopic variants: post-Born-Oppenheimer contributions

J Chem Phys. 2008 Jun 7;128(21):214306. doi: 10.1063/1.2929832.

Abstract

Adiabatic corrections are evaluated for the interaction of two hydrogen molecules (H(2))(2) and isotopic variants. Their contribution to the cluster formation amount up to 10% of the interaction energy. Added to the best ab initio Born-Oppenheimer isotropic potential, they correct especially its short range repulsive part. Calculations of second virial coefficients are improved in general, with an impressive agreement with experiments for gaseous D(2) in a large range of temperatures. The potentials are available in both analytical and numerical forms.