Title: Study of gas-phase reactions within the modified Marcus model. IV. Arrhenius equation for the reaction CH4 + CH3 -> CH3 + CH4
Abstract:Abstract The results of a theoretical study (energy calculation level UCCSD (T)/6-31+G**//B3LYP/6-31+G**) of methane with methyl radical gas-phase reaction kinetics (Comp. Theor. Chem. 1125 (2018), Co...Abstract The results of a theoretical study (energy calculation level UCCSD (T)/6-31+G**//B3LYP/6-31+G**) of methane with methyl radical gas-phase reaction kinetics (Comp. Theor. Chem. 1125 (2018), Comp. Theor. Chem.1179 (2020) 112767) were used to analyze the Arrhenius equation in the temperatures range 2000 - 10 K. A discussion within the framework of the previously proposed (Russ. Bull. Int. Ed. 2008, 57, 1842-1849) model, which is a modification of the non-equilibrium Marcus model, is based on direct ab initio calculations of the structure and energy of the varied activated reaction complex in a wide range of distances between the reactants. The Arrhenius equation is analyzed in terms of the change with temperature parameters in the reaction rate constant equation. The results obtained make it possible to distinguish three temperature ranges (2000 - 900, 900 - 100 and 100 - 10 K), which are qualitatively different from each other in the nature and degree of influence of various variable factors on the Arrhenius plot.Read More