Analytical potentials for triatomic molecules

Potential energy functions have been derived for the ground state surfaces of LiFH and H2F by fitting ab initio data. Standard deviations of ∼7 kJ mol-1 are obtained for both surfaces. For LiFH it is predicted that a stable linear hydrogen bonded complex exists with energy 11·5 kJ mol-1 below the Li + HF dissociation limit. These functions are valid for all configuration space. For H2F the surface is two-valued with a line of intersections in the space of C 2v structures. The correct saddle point behaviour for both the symmetric and asymmetric exchange reactions have been reproduced, a feature not previously reproduced by LEPS functions.