Force and density study of the chemical reaction process OH2+H+→OH3+

The force and density origin of the ionic reaction process OH2+H+→OH3 + is studied on the basis of the electrostatic force theory. In order to obtain reliable results, we have used the floating AO wavefunction (with minimal basis) which satisfies the Hellmann-Feynman theorem for the approaching proton. Accuracies of the results of the ordinary nuclear-centred AO wavefunction (with minimal basis plus polarization functions on hydrogen atoms) have been also examined. It is shown that the predominant origin of the driving force is the atomic dipole force which is caused by the transfer of the lone-pair density of OH2 into the atomic region of H+ and the succeeding inward polarization of the transferred electron density. The exchange force due to density accumulation in the forming O-H+ bond region is of secondary importance. This is in contrast with the previous results for the radical reaction processes. The present reaction may be regarded as the transformation of the lone pair into the bond pair.