MP2 AB-INITIO CALCULATIONS OF THE HEXAFLUOROBENZENE-BENZENE AND MONOFLUOROBENZENE COMPLEXES

Interaction energies for the C6F6-C6H6 and C6F6-C6H5F supermolecules h ave been investigated through pseudopotential SCF-MP2 calculations. Fo r both systems, a minimum in the interaction energy curve was found. F or C6F6-C6H6 this is in agreement with experimental evidence for the f ormation of a complex, while for C6F6-C6H5F the calculated interaction energy suggests the existence of this less symmetric complex. Well de fined minima were obtained for the interaction energy curves only afte r the inclusion of electron correlation. However, the difference betwe en the stabilization energies of the two complexes is determined by th e electrostatic contribution.