Temperature Dependence of Rate Constant for Tunneling Reaction HD + D → H +D_2 in Low Temperature Region 2.6-6.5 K: Experimental Evidence of Phonon-Assisted Tunneling

摘要

Rate constants for the tunneling reaction, HD + D→H + D_2, in solid HD have been determined by using ESR in the very low temperature range of 2.6 K - 6.5 K. The rate constants increase steeply with increasing temperature above 5 K, while they are almost independent of temperature below 5 K. The results above 5 K do not coincide with theoretical values calculated by the gas phase model. Phonon-assisted mechanism is proposed to account for the remarkable temperature dependence of the tunneling reaction in solid HD.