适用于若干生物大分子体系的紧束缚方法研究

项目名称： 适用于若干生物大分子体系的紧束缚方法研究

项目编号： No.20873075

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 电工技术

项目作者： 刘成卜

作者单位： 山东大学

项目金额： 33万元

中文摘要： 紧束缚方法是研究复杂化学体系的有效方法，但是经典的紧束缚方法不适用于研究生物大分子体系。我们通过较为深入的理论研究，建立了适用于生物大分子的紧束缚方法。我们采用紧束缚近似导出了生物大分子体系中的单电子运动方程，该方程中，势函数为每一格点Hartree-Fock势的直接和。分别对每一格点做从头算可以得到各个格点的势函数，然后就可以求解整个生物大分子体系中的单电子运动方程。在位能和迁移积分是两个非常重要的物理量，我们在接近从头算的水平上给出了在位能和迁移积分的计算公式，编写了计算程序，解决了在位能和迁移积分的计算问题。应用我们所发展的方法，较为系统地研究了影响生物大分子DNA在位能和迁移积分的各种因素，修正了文献中用经验方法给出的在位能和迁移积分数据，发现在DNA链上，势函数具有量子阱结构，进而研究了DNA中的各种元激发机理和有关的输运过程。此外，还修正了用于研究电荷传递的键耦合路径模型，应用我们修正的键耦合路径模型研究了蛋白质中的电荷传递路径，得到了与实验较为一致的结果。

中文关键词： 紧束缚方法；在位能；迁移积分；键耦合路径模型；生物大分子

英文摘要： Tight-binding (TB) method is an effective approach to study complicated molecular systems of large size. However, the classical TB method is not appropriate to biomacromolecules. Through thorough investigations, we have built up a TB method for biomacromolecules. A single-electron Schrodinger equation for biomacromolecules, of which the potential is a direct sum of Hartree-Fock potential at all sites in the molecule, has been put forward within the TB approximation. After getting the Hartree-Fock potential of each site by ab initio calculations, the single-electron Schrodinger equation for the whole biomacromolecule can be constructed. Both the on-site energy and transfer integral are very important quantities in the TB method. We have developed formulas and the corresponding programs to calculate them at the level of accuracy comparable to ab initio, so both the on-site energy and the transfer integral can now be obtained through theoretical calculation. Using our methods, we systematically investigated the factors that may influence the on-site energy and transfer integral, and based on our calculations, we modified the previous empirical parameters for the on-site energy and transfer integral presented by other references. We also discovered a quantum-well-like structure along the DNA chain, and investigated the elementary excitation mechanism and charge transfer process in DNA molecules. Besides, we have modified the through-bond coupling (MTBC) model that usually used to study the electron transfer process, and by our new model the electron transfer pathway in protein was studied with the results in good agreement with experiments.

英文关键词： Tight-binding method; On-site energy; Transfer integral; modified through-bond coupling model; Biomacromolecule