| The radicals often exist in gas-state combustion reaction of hydrocarbon decomposition. These radicals are the main factor of the combustion products. Therefore, such experimental and theoretical research have been attached much importance recently. Of all, the radical of the methane decomposition is the most. The effective method of disposing halohydrocarbon is decomposition, however, decomposition is the main reason of the second pollution. How to eliminate the environmental pollution through controlling the decomposition process is becoming the most important problem, and it is also the focus on the environmental chemistry and kinetics chemistry especially in recent years. In order, to control these pollution effectively, we must learn the mechanism of the various combustion reaction. However, the research report on such reaction is very little, or only analyzing the mechanism on bond length and energy. We are the first who investigate the reaction mechanism on the vibrational frequencies and vibrational modes.In this paper, we investigate the multi-channel radical reaction mechanism mainly employed the Density Function Theory method. Choosing two gas state molecular react, illuminate the reaction mechanism by analyzing the vibrational modes.This paper includes six chapters. The first chapter can be divided into three parts. The first part briefly introduces the theoretical background and related contents of the multi-channel reaction. The second part narrates the development and research status of the vibrational spectrum theory resumptively. The third part expounds the primary work of this paper. The second chapter introduces the related calculating methods which are used in this paper. By comparing the methods, finally we thought that the DFT method is the best and we used it throughout the research. The third chapter mainly introduces the IR basic knowledge. In brief, the formerchapters mainly discuss the theoretical surrounding and bases, so that they offer the reliable quantum chemistry methods.On the basis of the basic theory, the fourth chapter investigates thereaction between the Cl atom and CFhCO, owing to its variety reaction mechanism. All the calculation employed the mixed-DFT method (DFT桞3LYP) on the 6-311++G (d, p) basis set. We optimized configuration of all the species in this reaction (reactants, intermediate states, transition states and products); we also analyzed the vibrational frequencies of all the species on the basis of the optimized equilibrium conformation and assigned the vibrational modes. During analyzing the frequencies, we found that the image frequency is often connected with such bonds which are to be ruptured and formed. The structure of one species changed and then its frequencies and vibrational modes also changed correspondingly. There must have some relation between them, so it is reliable to explain the reaction mechanism through vibratinal modes. If a bond is prolonged or weakened, the frequencies are red-shifted; on the contrary, if the bond is shortened and strengthened, the frequencies are blue-shifted. So the changes of the vibrational frequencies and vibrational modes must be relative to the transformations of the structures. Furthermore, we described the changes on the potential energy surface with the multi-channels on the basis of all the species energies. We can find that the reactorsâ†'IMlâ†'TSlâ†'IM2â†'TS4â†'CO and CH2C1, this channel is the feasible. So the mechanism is clear.In the fifth chapter, we choose another interesting reaction which is the multi-channel decomposition of the CH3OF. We employed the samemethod and basis set (B3LYP/6-311++G (d, p)) and calculated the equilibrium structures, total energies and vibrational frequencies of all the species. With analyzing the changes on the potential energy surface, there have 3 main channels of the CH3OF decomposition. Absorbing little energy, CHjOF can become the cis-CH3OF and then turn into TS1 through a not very high active energy, finally form the main products HF... |
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