掺杂剂对聚乙炔性质影响的理论研究

The Theoretical Study of the Effects of Dopants on the Properties of Polyacetylene

以多烯烃模拟聚乙炔链,用CNDO/2方法讨论了各种掺杂剂对聚乙炔性质的影响,掺杂剂使孤子宽度收缩变窄,且p型掺杂剂比n型掺杂剂的影响更大,掺杂剂影响聚乙炔链中的电荷密度波,使电荷主要集中分布于掺杂剂附近的碳原子上。掺杂碱金属时,掺杂剂原子的最高占据轨道与聚乙炔中孤子自旋轨道之间的作用由Li到K依次增强,解释了ESR实验结果。

A finite polyene C29H31 is employed to simulate the conjugated polymer molecule of polyacetylene. The effects of various dopants on soliton in polyacetylene were studied by using CNDO/2 level semiempirical quantum chemical method. The width of soliton is contracted when dopant is present. The effects of p-type dopants are greater than those of n-type ones. The charge density wave in polyacetylene chain is affected by the dopants and is closed to near the carbon atom of the soliton. The action between HOMO of dopant atom and spin orbital of soliton in the polyacetylene strengthened in proper order from Li to K, when the alkali metal is present, and the experiment result of ESR was explained.