BENZENE O-2 INTERACTION POTENTIAL FROM ABINITIO CALCULATIONS

The interaction potential between benzene and O2 has been computed by means of SCF/MP2 calculations. The dominant attractive interaction is due to dispersion forces, therefore the choice of the basis set has been dictated by the requirement that the polarizabilities of the two partners be correctly reproduced. Basis set superposition error has been corrected for by the counterpoise technique. According to the present results, in the complex O2 is parallel to the benzene plane. The computed dissociation energy is D(e) = 1.24 kcal/mol, which should be corrected upward to about 1.5. The ab initio results have been fitted by different analytical potential functions, including the atom-atom Lennard-Jones 6-12 formula and those used in several force-fields: MM2, MM3, ECEPP, CHARMM, AMBER, OPLS.