紧束缚模型方法及其在DNA分子中的应用

Tight-binding model method and its applications in DNA molecules

近年来,紧束缚模型方法被广泛应用于计算生物大分子体系.本文从第一性原理出发,根据紧束缚近似的思想,推导出生物大分子体系中的单电子运动方程.在此基础上给出了紧束缚模型方法中所涉及参数(在位能和迁移积分)的计算公式,在理论上完善了紧束缚模型方法.我们将所提出的参数化方法应用于理想B型DNA分子,给出了各种序列组合下的在位能和迁移积分.此外,我们还计算了周期性DNA分子poly(A)-poly(T)和poly(G)-poly(C)中空穴在位能和迁移积分随格点间距离的变化,为改进现有的SSH极化子模型提供了新的思路,有助于DNA中电荷输运的极化子机理的研究.

Tight-binding model method is an effective approach to study complicated molecular systems with large sieze.According to the idea of tight-binding approximation,we have derived the single-electron motion equation for biomacromolecule systems and formulas for calculating parameters（on-site energy and transfer integral） in the related tight-binding model.The tight-binding model method has been modified and a parametrization scheme has been proposed.With the scheme,we calculated the parameters used in tight-binding model of the ideal B-form DNA molecules.Utilizing these parameters,the tight-binding model Hamiltonian matrix for holes or electrons can be constructed,and then,the states of holes or electrons can be described.In addition,we studied the dependence of on-site energy and transfer integral for the periodic DNA molecules poly（A） -poly（T） and poly（G） -poly（C） on the distance between adjacent basepairs.These results provide some new sights for modifying the classical SSH model for DNA molecules,which may be helpful to the studies on the polaron mechanism of charge transport in DNA molecules.