A new expression for the direct quantum mechanical evaluation of the thermal rate constant

摘要

Based on the formalism of Miller,Schwartz,and Tromp [J.Chem.Phys.79,4889(1983)],we derive a new expression for the thermal rate constant for a chemical reaction.The expression involves an unperturbed,i.e.,reactant or product channel Boltzmann operator for the imaginary time propagation,making it possible to compute efficiently the rate constant for a range of temperatures.We illustrate numerical aspects with an extensive study of the one-dimensional Eckart barrier problem,as well as a study of the three-dimensional (J=0) D+H_2 problem.