Bochenkova Anastasia V, Bochenkov Vladimir E, Khriachtchev Leonid
Department of Chemistry, M. V. Lomonosov Moscow State University, 1/3 Leninskie Gory, 119991 Moscow, Russian Federation.
J Phys Chem A. 2009 Jul 2;113(26):7654-9. doi: 10.1021/jp810457h.
The thermal conversion of HArF configurations in solid argon has been investigated both experimentally and theoretically. The matrix isolation experiments have been concentrated on temperatures 25-27 K, promoting the transition from the unstable to stable HArF configuration. The combined quantum mechanical-molecular mechanical and temperature-accelerated dynamics approach has been developed to study the real-time evolution of HArF trapped in different matrix-site morphologies. Two realistic pathways of the stable HArF formation are found for annealing at 25-27 K. The conversion mechanism in both pathways involves the local mobility of matrix vacancies in the vicinity of the HArF molecule. These two relaxation processes occurring within different timescales can cause the multiexponential decay of unstable HArF observed experimentally. The theoretical values of the activation energy of 64 meV as well as the corresponding pre-exponential factor of exp(28) s(-1), obtained for one of the unstable HArF configurations, are well consistent with the experimental estimates of 70 meV and exp(30 +/- 3) s(-1), respectively.
已通过实验和理论研究了固态氩中HArF构型的热转化。基质隔离实验集中在25 - 27K的温度下，促使从不稳定的HArF构型向稳定构型转变。已开发出量子力学 - 分子力学与温度加速动力学相结合的方法，以研究被困在不同基质位点形态中的HArF的实时演化。在25 - 27K退火时发现了稳定HArF形成的两条现实途径。两条途径中的转化机制都涉及HArF分子附近基质空位的局部迁移。这两个在不同时间尺度上发生的弛豫过程会导致实验中观察到的不稳定HArF的多指数衰减。从一种不稳定的HArF构型获得的64meV的活化能理论值以及相应的exp(28) s(-1)的指前因子，分别与70meV和exp(30 +/- 3) s(-1)的实验估计值非常一致。
