A NEW AB-INITIO BASED 6-DIMENSIONAL SEMIEMPIRICAL PAIR INTERACTION POTENTIAL FOR HF

We present an analytical pair potential for hydrogen fluoride based on 3284 ab initio points at counterpoise-corrected MP2-R12 and lower lev els using a large basis set. Empirical refinements are applied through comparison of experimental data with solutions of the multidimensiona l nuclear Schrodinger equation and appropriate mixing and scaling of t he ab initio data. The new potentials are compared to previous dimer p otential hypersurfaces and spectroscopic data, yielding best estimates of 19.1(2) kJ/mol for the dimer dissociation energy D-e and 4.2(2) kJ /mol for the electronic hydrogen bond tunneling barrier.