Molecular Dynamic Calculation On The Reaction Of Several Radical

In this Paper,high-level quantum chemistry calculation methods are used to theoretically investigate on the potential energy surfaces of some radical reactions which are important in atmosphere,combustion and surface chemistries. Much kinetic information of these reactions was obtained. The results presented in this paper may be very helpful for understanding the related radical reactions in atmosphere,combustion and surface chemistries,and may provide some elemental theoretical basis for futher experiments on radical reactions. The whole paper consists of four chapters.Chapter one mainly reviews the evolution of chemical and radical reactions. The second chapter summarizes the theory of quantum chemistry and calculation methods of this paper.In the third chapter, the reaction of HO₂ radical with SO₂ was studied, Using the density function theory and CBS methods. At the B3LYP/6-311++(d, p) level, the geometries of all species (reactants, intermediates, transition states and products) were optimized. At 298.15k and 300k, all the energies of the species were obtained with the correction of ZPVE at the CBS-QB3 level. The calculated results indicate that the major pathways of the reaction is the O atom of HO₂ radical to attack S atom of SO₂ molecule, forming the isomer IM2(HSO₄),then decompounding follows, producing P1(OH+SO₃) with the reaction heat of 72.9KJ·mol^-1,and it is in agreement with the results of experiment.In the fourth chapter, the decomposition reactions of C₉H₁₂^+· system have been studied extensively at the B3LYP/6-311++G(d, p) level with Gaussian 98 program package. the geometries of all species (reactants, intermediates, transition states and products) were optimized. All reaction channels were fully investigated with the vibrational mode analysis to confirm the transition states and with electron population analysis to discuss the electron redistribution, and to elucidate the reaction mechanism. The reaction mechanism shows that there is a non-barrier channel of C₉H₁₂^+·→C₇H₇⁺+C₂H₅^·, which is thermodynamically most favorable.