The weak Li-2-He interaction revisited: A combined ab-initio and empirical modelling.

The potential energy surface (PES) for the interaction between Li-2((1)Sigma(g)(+)) and He-4 has been computed earlier by using an accurate, post-Hartree-Fock quantum calculation for its ground electronic state and was presented in previous papers(1,2). Here we report a revised version of the same interaction that we have generated using instead an empirical approach that replaces the two-body contributions in the ab-initio potential with external estimates. We have repeated Diffusion Monte Carlo calculations to obtain the quantum ground states for the Li2Hen clusters already discussed in our previous paper(1) and we compare the two sets of findings.