在紧束缚模型基础上,研究了位置涨落对碱基对周期排列的有序DNA分子的能带结构和电子态的影响,并分析了DNA分子的导电性.计算发现:随涨落的增强,带隙变小,同时,电子态倾向于局域化.室温下DNA分子的导带底电子态将呈现出较强的局域行为,因此,即使对有序排列的DNA分子,带输运理论在室温下也可能不再适用.
In the framework of a tight binding model, effect of the lattice site position fluctuation on the energy band and the electronic states of DNA is studied by means of stimulation with the square distribution. Effect of the position fluctuation on the conductivity of DNA is also analyzed. It is found that with the enhancement of the fluctuation the band gap becomes smaller and the electronic states become localized. The electronic states around the bottom of conductance band appear apparently localized with a room temperature fluctuation. Therefore, even if these base pairs were arranged orderly, the band resonant charge transport mechanism might not be suitable for DNA at room temperature.