Abstract :
The rate constants for recombination and exchange processes are studied in terms of two different flux correlation approaches: one is the Yamamoto approach, which is based on the linear response theory, and the other is the Miller one. Using those approaches we consider two exactly solvable cases, i.e., the free particle and the parabolic potential models. Since the rate constants for recombination and exchange processes are calculated by Laplace transforms of the flux correlation functions, the two approaches give different results. In the present calculation, we find that the rate constant in the Yamamoto approach is larger than that in the Miller approach by about 40% at low temperature (~100 K) and high pressure (~1 GPa). The difference is considerable in the region where quantum effects dominate.
