| Electron transfer is ubiquitous in biological, physical, inorganic, and organic chemical systems. According to the components of the reactants, the electron transfer reactions can be divided into three types: self-exchange reactions, cross reactions and bond-rupture electron transfer reaction. Among them the bond-rupture electron transfer reaction is the most important and complicated for most actual reactions involving the breaking of chemical bonds and the forming of new ones. With the rapid progress of the technology, especially the wide application of high qualitative computer to the electron transfer reactions, the bond-rupture electron transfer reactions become the theoretical and experimental interest in physical chemistry and biology. With the help of the computer, predicting of the possibility for the reaction from the theory directly has been realized in recent years. On the basis of the experimental data, classical and quantum chemistry methods are used to theoretically investigate two typical ET bond-rupture reactions. Comparison of the calculation results to the experimental data showed that the methods used in the paper are reliable and the conclusions derived from the calculation are in agreement with the experimental data.The whole paper consists of four sections. The first section is the introduction, and it mainly describes the general electron transfer theory's developing process and some studies and theoretical models about the bond-rupture electron transfer reaction. Because the quantum chemistry theory, electron transfer theory will be involved in possessing the electron transfer reactions, so in the second section some relevant theory methods and principles are described. In the third section the ab initio method and density functional theory (DFT) method were used to investigate the reaction mechanism and properties for F+H2->HF+H reaction. In the process of optimizing all species involved in the reaction, the collinear precursor complex was found to be the most stable; for the transition state, the collinear one had been optimized and the corresponding energy had been given, thus the adiabatic activation energy can be derived. The electron transfer reaction mechanism had been discussed through analyzingthe charge population of various species and the vibraional modes and vibrational frequencies, the results were in agreement with the postulation that the electron began to transfer in the transition state region. According to the potential energy curves of the reactants and products, the Hjf was derived, and some thermodynamic parameters such as activation energy, recorganizational energy were also given on the basis of optimization, thus the rate constant k can be derived.In the fourth part, the theoretical investigation for the multichannel bond-breaking electron transfer reaction involving the Chlorine Nitrate(ClONO2) have been done using density functional theory. In the calculation process, first, the structure and energy of the reactant C1ONO2 have been investigated using HF method and various density functional theory methods including BLYP, B3LYP, B3P86 and B3PW91 at 6-31 l++g** basis set, and on the basis of the geometry optimization, the harmonic vibrational frequencies of the ground state reactant have also been predicted using above-mentioned methods comparing to the CCSD(T) method. Among them the B3LYP results were in good agreement with the experimental fundamental vibrational frequencies while the HF method was the worst agreement one. This result showed that the DFT method is superior to other ab initio methods in optimizing geometry and predicting vibrational frequencies and it is a more cost-effective in comparison with the CCSD(T) method. Then, thedissociation electron transfer reaction mechanisms of C10NO: fcl Cl+ NO3 and two correlative reactions have been investigated through the relative energies, vibrational modes of transtion state and internal reaction coordinate (IRC) calculation. Finally, the potential energy surface protracted according to... |
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