The Quasi-one-dimensional Copolymers Charge Transfer Properties Of DNA Molecules

In this thesis, the basic conception and structures of DNA molecules, and the newest research development about the phenomenon of charge transfer and the mechanism were introduced. The question of whether DNA is able to transfer electrons has attracted much interest, particularly as this ability may play a role as a repairing mechanism after radiation damage to the DNA helix. It was demonstrated that the base pair stack within double helical DNA provides an effective medium for charge transfer.Charge transfer in super-molecular assemblies of DNA is particular because of the notion that the π-stacked bases within the duplex may mediate the transfer, possibly leading to damage and/or repair the DNA chain. The phenomenon of transfer through π-stack arrays over a long distance has an analogy to conducting in molecular electronics. DNA can be considered as a one-dimensional, aperiodic, linear chain of stacked base pairs. More than 30 years ago, it was suggested that duplex DNA might support electron transport in a manner similar to that of the linear-chain compounds, namely, by tunneling along overlapping p orbital located on the base pairs.According to the definition of the homopolymer and the copolymer in the organic macromolecule, we can regard the DNA molecule that made of the same base as the homopolyer DNA molecule. Similarly, the DNA molecular, which is composed by different bases through connection by covalent bond, is also considered as a conjugated copolymer.In this work, two kinds of DNA coupling electronic characteristic, within the extended one-dimensional tight-binding model were studied. If two kinds of DNA which having different the potential energy to couple, then the charge transfer will spontaneously occur, which does not need photo excitation. This phenomenon is similar to the character of the p-n knot. Therefore, it has the extremely vital significance in both experimental and theoretical aspect. The mechanism of charge transfer in DNA copolymers and the factors of which affected the number of charge transfer is analyzed. The concrete research contents and the results are given as...