On the bonding and structure of ethylene-BrCl adducts

Geometric structures, limited sections of the potential surface and dipole moments of the ethylene-BrCl complex have been computed using the MP2 method and a double zeta+polarization basis set. The theoretical results confirm the experimental observation of a π adduct of neutral monomers. The complex is bound by 0.23 eV with respect to dissociation to ethylene+BrCl and 5.75 eV with respect to dissociation to ethylene-Br+ + Cl−. The evolution of the outer, π complex of neutral ethylene and BrCl into the inner, ionic one is rationalized in terms of interactions of the covalent and ionic potential surfaces.