DISSOCIATION-ENERGY OF THE BENZENE WATER VAN-DER-WAALS COMPLEX

The dissociation energy of the complex C6H6.H2O was determined by the threshold difference method. These complexes were produced in molecula r beams via the expansion of a mixture of helium, and benzene and wate r vapors in the ratio of 96:3:1. The method requires the ionization po tential of C6H6 and the appearance potential of C6H6+ from C6H6.H2O, t he difference between which is the dissociation energy. The necessary values are 9.246 and 9.344+/-0.012 eV, respectively, from which D(C6H6 .H2O) = 0.098+/-0.012 eV = 2.25+/-0.28 kcal mol(-1). The ionization po tential of C6H6.H2O is 9.170 + 0.014 eV, which leads to the dissociati on energy of the complex ion of D([C6H6.H2O](+)) = 4.0+/-0.4 kcal mol( -1).