Electrostatic model for the interaction force constants of the formic acid dimer

A new form of the intermolecular potential that conforms with ab initio structures, interaction energies, interaction forces, intermolecular force constants and dipole derivatives of four different hydrogen-bonded structures of the formic acid dimer, was developed. The ab initio data were based on a scaled HF/6-311++G** force field in nonredundant coordinates and indicate a reassignment of some bands in the spectrum. The model considers charges, charge fluxes, atomic dipoles and van der Waals interactions, and can reproduce intermolecular force constants.