Variational transition state theory evaluation of the rate constant for proton transfer in a polar solvent

The rate constant for proton transfer in a polar solvent was calculated using variational transition state theory (VTST). The effects of solvation on reaction dynamics were modeled using a generalized Langevin equation (GLE) for the solute. The GLE solvation dynamics were approximated by a collection of harmonic oscillators. The computed rate constants and H/D kinetic isotope effects were compared with the results obtained from calculations using other approximate dynamical theories including approaches based on one-dimensional models, molecular dynamics with quantum transitions and path integrals.