Previous work (Comp. Theor. Chem. 1125 (2018) 142-151) was devoted to research in the framework of the modified Marcus model (calculation level UCCSD (T) 6-311++G**// B3LYP/6-31+G**) on the reaction kinetics of methane with a methyl radical in the temperature range of 10 - 800 K. In the present work, these studies are extended to the region of high temperatures, up to 2000 K. Analysis of data on the kinetics and KIE in the temperature range of 250 - 2000 K is carried out in comparison with the data of studies performed using the quantum scattering method (SM Remmert, ST Banks, DC Clary, J Phys. Chem. 113 (2009) 4255-4264). The abnormally high values ​​of k_H/k_D observed in our work are considered a consequence of a violation of the generalized Frank Condon principle (GFCP) for the deuterium atom transfer reaction. The influence of steric factor on the value of k_H/k_D is quantitatively analysed; the similarity of the obtained picture to similar observations for the reaction of enzymes is noted.

先前的工作（Comp。Theor。Chem。1125（2018）142-151）致力于在改良的Marcus模型（计算水平UCCSD（T）6-311 ++ G ** // B3LYP / 6- 31 + G **）在10-800 K的温度范围内研究甲烷与甲基自由基的反应动力学。在目前的工作中，这些研究扩展到了高达2000 K的高温区域。数据分析与使用量子散射方法进行的研究数据（SM Remmert，ST Banks，DC Clary，J Phys.Chem.113（2009）4255）进行了比较，研究了在250-2000 K温度范围内的动力学和KIE -4264）。k _H / k _D的异常高值在我们的工作中观察到的结果被认为是氘原子转移反应违反通用弗兰克·康登原理（GFCP）的结果。定量分析了空间因素对k _H / k _D值的影响；注意到获得的图片与酶反应的相似观察结果的相似性。