Journal of Physical Chemistry A, Vol.106, No.47, 11616-11622, 2002
Comparative study of identity proton-transfer reactions between simple atoms or groups by VB methods
Valence bond SCF calculations have been carried out on identity proton transfers of the type X-H + X- X- + H-X and X-H+ + X --> X + X-H+ for systems where X = F-, Cl-, Br, OH-, SH-, NH2-, PH2-, CH3-, SiH3-, OH2, NH3, and PH3. A hybrid consisting of three contributing structures-reactantlike, productlike, and ionic (X- H+ X- or X H+ X)-gives reasonable results, though additional structures afford a slight further decrease in energy. Energies somewhat below Hartree-Fock and reasonable weights are obtained. Calculated barriers agree well with those obtained by high-level ab initio calculations with correlation. Insights into the factors determining barrier height are obtained.