六元杂环分子电学特性的理论研究

在第一性原理基础上，利用弹性散射格林函数方法，研究了六元杂环分子结2,5-哒嗪二硫酚 、2,5-吡嗪二硫酚和2,5-嘧啶二硫酚的电子输运特性，分析了终端原子的选取对杂环分子吡 啶电学特性的影响. 利用分子前线轨道理论和微扰方法定量地确定了分子与金属的相互作用 能参数. 计算结果表明，2,5-哒嗪二硫酚具有较好的电学特性，而2,5-嘧啶二硫酚在外加电 压较低时电导值比较小. 对于吡啶分子，选取硒原子作为终端原子时，其导电特性优于分别 以氧原子和硫原子作为终端原子的情况. 关键词： 六元杂环分子 伏安特性 电子输运 分子电子学

Theoretical studies on electronic transport properties of six-membered heterocyclic molecules

By applying the elastic scattering Green's function theory in combination with the hybrid density function theory, the electronic transport properties of molecular junctions constructed by the six_membered heterocyclic molecules, pyridazine_2,5_dithiol, pyrazine_2,5_dithiol, and pyrimidine_2,5_dithiol, have been studied. For the heterocyclic molecule pyridine, the influence of the terminal atoms on the current_voltage characteristics has also been obtained. We have accurately determined the coupling constant between the molecule and electrodes by using the frontier molecular orbital theory and the perturbation method. The numerical results show that pyridazine_2,5_dithiol has higher current and conductance, while the conductance of pyrimidine_2,5_dithiol is very small when the bias voltage is lower than 4V. The conductivity of the molecule pyridine with selenium atom as the terminal atom is higher than that with oxygen atom or sulfur atom.