Computed potential hypersurface (including electron correlation) of the system Li+/H-2

The potential hypersurface of the system LiH2* is calculated in the Hartree-Fock approximation and with the IEPA PNO method (including electron correlation). The basis set consists of gaussian lobes. The region of H-H distances considered is 0.9 to 3 a(o) (occasionally to 5 a(o)) whereas the distance of the Li nucleus to the midpoint of the H-2 subunit is varied between 1 and 15 a(o). The angular dependence of the hypersurface is investigated as well. The maximum overall error (except for a parallel shift of the whole hypersurface) is estimated to be less than 0.002 au and even smaller in more limited regions of space. The role of the correlation energy is discussed and the asymptotic behaviour of the Li+/H-2 interaction is compared with results from perturbation theory. The results arc given both as tables of numbers and in the form of an analytic fit. The change of energy, equilibrium distance and force constant of the H-2 as a function of the approach of the Li+ is also tabulated.