AB-INITIO GROUP MODEL POTENTIALS - APPLICATION TO THE STUDY OF INTERMOLECULAR INTERACTIONS

A method for the determination of ab initio group model potentials within the Hartree-Fock framework is reported. The theoretical formulation is based on the core model potential approach and allows the replacement of a group by a polycenter model potential having a local molecular symmetry. Model potentials for the Ne atom and the HF molecule are obtained and used in Hartree-Fock calculations of the NeHF and (HF)2 complexes using a triple-zeta plus polarization (TZP) basis set. Radial and angular properties of these model potentials are analyzed and compared with all electron reference calculations. The method is free of basis set superposition error and gives binding energies in agreement with Hartree-Fock calculations. The suitability of the method for the study of intermolecular interactions of larger systems is discussed.