ELECTROSTATIC MODEL FOR THE INTERACTION FORCE-CONSTANTS OF THE FORMIC-ACID DIMER

We have developed a new form of the intermolecular potential that is c onsistent with ab initio structures, interaction energies, interaction forces, intermolecular force constants, and dipole derivatives of fou r different hydrogen-bonded structures of the formic acid dimer. The a b initio ''data'' are based on a scaled HF/6-311++G* force field in n onredundant coordinates and reflect a reassignment of some bands in th e spectrum. The model incorporates charges, charge fluxes, atomic dipo les, and van der Waals interactions, and its successful reproduction o f the intermolecular force constants indicates that it may provide a m ore general description of detailed features of the hydrogen bond.