Complexes of HNgY with HX (Y, X = F, Cl, Br, I): Symmetry-Adapted Perturbation-Theory Study and Anharmonic Vibrational Analysis

We performed the first comprehensive analysis of the intermolecular interaction energy and anharmonic vibrations of 41 structures of the HXeY···HX (X, Y = F, Cl, Br, I) family of noble-gas-compound complexes for all possible combinations of Y and X. New structures are found and the interaction energy is studied by means of the symmetry-adapted perturbation theory up to the second-order corrections providing insight into the physical nature of the interaction in the complexes. The energy components are discussed in connection to anharmonic frequency analysis. The results show that the induction and dispersion corrections are the main driving forces of the interaction and their relative contributions correlate with the complexation effects seen in the vibrational stretching modes of Xe-H and H-X. Rather clear patterns of interaction are found for different structures. Our findings corroborate previous findings with better methods and provide new data. The results suggest that the entire group of the studied complexes can be labelled as ''naturally blue-shifting'' except for the complexes with HI.