Tight-binding Method Of Dna Electronic Structure And Polarization Of Sub-transmission Study

DNA is the most important molecule of bioorganic system. Its structure contains information that determines heredity, cell division, growth and biosynthesis of protein. Interference with gene function and prevention of transcription and translation can kill invading microorganisms or tumour cells. In recent years, the charge migration along the duplex DNA stack is attracting considerable interest for the biochemical reasons in life science, as well as for the possible applications in molecular electronics. A number of experiments have showed that, the product of electron transfer will lead to DNA mutation, light-induced electron transfer will damage DNA, or repair it to cure tumour. For example, under the irradiation of the ionization or ultraviolet radiation, an electron in DNA will move along DNA before being traped by other atoms. So it is thought that DNA may be a quick channel for electron transfer which is independent of distance. Therefore, if DNA is a conductor, it will be the ideal material for nano-line and molecular electronics. At present, the mechanism of DNA electron transfer has been still a puzzle now. So how to explain these phenomena, ravel the mechanism of electron transfer, and explain theoretically the mutation and repair law for DNA, which are the most important problems in life science. Progress in related research has great meaning in the knowledge of biological system and the design of gene with protein drug, especially in the cancer therapy.The biology molecules DNA have two characters. One is the large size, the other is the complicated structure. The classical theoretical chemistry methods can offer relatively accurate results for middle-size molecules, but it is difficult for it to deal with the complicated biology molecules. So it is important to develop the theoretical chemistry methods for the complicated biology molecules.At present, there are two calculation methods for material properties. One is ab initio method, namely, First-principles. It does not need any experiential data. The other is the semi-empirical method, which is based on some existent experiment results. Ab initio method is the most essential theoretical method for chemistry...