Polarization model study of isotope effects in the gas phase hydronium–hydroxide neutralization reaction

Using the polarization model to represent all interactions present, classical dynamical trajectories have been numerically generated for reactive collisions between hydronium and hydroxide ions. The four isotopic variants have been examined that are possible with reactants H3O+, D3O+, OH−, and OD−; 100 trajectories were created for each case. The results show a marked tendency for energy released by the neutralization to be concentrated on that water molecule whose oxygen originated in the hydroxide anion. Significant isotope effects appear in the various product distributions, the primary determinant of which is the mass of the transferred hydrogenic particle. These effects appear to stem from differences between the respective lifetimes of the reaction complexes.