Temperature dependence of cryochemical H-tunneling reactions

The temperature dependence of tunneling transition of the atomic particle i n solids is studied near absolute zero. The different mechanisms of the tem perature dependence are considered. They are the medium reorganization, the potential barrier parameters modulation, and the under-barrier friction Th e nonadiabatic effects are also considered. The rate constant K is describe d by formula ln K=ln K-0+C4T4+C5T5+C6T6+C8T8 at low temperatures. It was co nducted through the comparison of theory with the experimental data from th e article of Kumada [Chem. Phys. Lett. 261, 463 (1996)]. It turned out that good agreement takes place if one takes into account the quantum propertie s of the hydrogen crystal with the assumption of the dominated role of medi um reorganization. (C) 2000 American Institute of Physics. [S0021-9606(00)5 0824-1].