A simple quantitative model of hydrogen bonding

Abstract

A simple model for the computation of intermolecular interactions is described. It consists of atom–atom potentials for the representation of repulsion and dispersion energies, and an evaluation of the electrostatic energy in terms of partitioned multipole moments of the monomer electron distributions. Applications are given in detail for hydrogen-bonded dimers of the molecules HF, HCl, CO, N2, Cl2, HCN, CO2, N2O, OCS, HCCH, NCCN, and HCCCN, and the results compared with ab initio and experimental results. Hydrogen bond energies are obtained to better than 4 kJ mol−1, intermolecular separations to typically better than 0.15 Å, and intermolecular angles within 5°, all compared with experiment. Force constants and vibrational frequencies are also well reproduced.