中文摘要：

基于一维紧束缚Su-Schrieffer-Heeger模型,采用分子动力学方法,讨论了杂质势的强度和杂质之间的距离对电子和空穴极化子动力学性质的影响.研究结果表明：1）当杂质势强度保持不变时,两杂质离子之间的距离（d）在2—16个晶格常数变化时,电子极化子的平均速度大于空穴极化子的平均速度,这是由于电子、空穴极化子与杂质势的库仑作用不同而产生的差异,同时极化子的平均速度随d的增加而增大;若继续增加杂质离子之间的距离,电子和空穴极化子的平均速度几乎保持不变,仅有一些微小的振荡,这是由于不同距离的杂质离子对电子和空穴极化子产生的势垒或势阱的叠加效果不同而引起的;2）保持两杂质离子之间的距离不变时,随着杂质势强度的增大,电子和空穴极化子的平均速度均减小,且空穴极化子的平均速度减小趋势更明显。

英文摘要：

Based on the one-dimensional tight-binding Su-Schrieffer-Heeger model, and using the molecular dynamics method,we discuss the dynamics of electron and hole polarons under the influence of impurity potentials and the distance between impurities. Under an external electric field, the electron or hole polaron can move along the polymer chain with a steady velocity. When the polarons collide with impurities, the velocities of the polarons would be affected by the impurity potentials and the distance between the impurities. 1） Firstly, at a fixed impurity potential strength, the average velocities of the electron and hole polarons as a function of the distance（2–16 times the lattice constant） between impurities have been discussed in polymers. It is found that the average velocities of the electron and hole polarons increase with increasing distance between impurities. It is worth noting that the average velocities of the electron polarons are greater than those of the hole polarons, which results from the fact that the electron and hole polarons have different coulomb interactions with the impurity ions. That is to say, the coulomb repulsion is shown between the electron polarons and impurity ions, which is similar to the potential barriers; while the coulomb attraction appears between the hole polaron and impurity ions, which is similar to a potential well. However, as the distance between the impurity ions becomes large enough, the average speeds of the electron and hole polarons almost remain the same, and show just a few small oscillation. This is due to the different distances between impurity ions which generate the different superposition effects of barrier or potential well on the electron and hole polarons. 2） Next, with a fixed distance between the two impurity ions, we find that with the increase of impurity potential strength, the average velocities of the electron and hole polarons decrease. And the decrease of the average speed of the hole polaron is more obvious. It can be explained as follow