Trakhtenberg L I, Fokeyev A A
SSC RF Karpov Institute of Physical Chemistry, 10 Vorontsovo pole Str., Moscow, 105064 Russia.
J Phys Chem A. 2007 Sep 27;111(38):9509-15. doi: 10.1021/jp073258l. Epub 2007 Sep 7.
In the frame of the radiationless transitions modified theory, the analytical expression of a rate constant of the chemical reaction with an atom tunneling is found for the case of a continuous spectrum of a phonon subsystem. Two mechanisms of temperature dependence of a rate constant are taken into account, the oscillations of the potential barrier of the reaction at the intermolecular vibrations and media reorganization. The simple expressions for temperature and pressure dependencies of a rate constant are obtained in the special case of lattice motion-the Debye model. The well-known Marcus expression for the rate constant of an electron transfer in the Debye phonon spectrum is deduced first. The pressure dependence of the reorganization energy of the media is derived. Comparison of the theoretical results with the literature experimental data on H-atom tunneling in the fluorene-acridine crystal, taking into account four promotive modes (translational, librational, and two low-frequency intramolecular modes at 95 and 238 cm(-1)) and the frequency dependence of the Grueneisen parameter, is fulfilled. Good agreement of the theory and experiments is observed.
在无辐射跃迁修正理论的框架下，针对声子子系统连续谱的情况，找到了具有原子隧穿的化学反应速率常数的解析表达式。考虑了速率常数温度依赖性的两种机制，即分子间振动时反应势垒的振荡和介质重组。在晶格运动的特殊情况——德拜模型中，得到了速率常数对温度和压力依赖性的简单表达式。首先推导了德拜声子谱中电子转移速率常数的著名马库斯表达式。得出了介质重组能的压力依赖性。考虑了四种促进模式（平移、转动以及95和238 cm⁻¹处的两个低频分子内模式）和格鲁尼森参数的频率依赖性，将理论结果与芴 - 吖啶晶体中氢原子隧穿的文献实验数据进行了比较。理论与实验结果吻合良好。
