Potential Energy Surfaces for Water Interacting with Heteronuclear Diatomic Molecules: H2O–HF as a Case Study

We present an analytical model, suitable for molecular dynamics applications, of a five-dimensional potential energy surface, based on the expansion in spherical harmonics, for non-linear-triatomic molecule (C2v) – heteronuclear-diatomic molecule systems, with both molecules having a rigid structure. The method consists in the exact transformation of quantum chemical input data related to a minimal number of significant configurations. This approach is applied to the case study of H2O–HF at various levels of theory. The interaction potential has been analyzed and compared with state-of-art theoretical models. Pros and cons of the method are presented and discussed.