高分子中的电子-声子相互作用与非线性光学极化率

ELECTRON-PHONON INTERACTION AND NONLINEAR OPTICAL SUSCEPTIBILITY OF POLYMER

反式聚乙炔的三次谐波产生谱(THG)在0.6和0.9eV处有两个共振峰。现有的各种理论都不能满意地解释第二个共振峰。只有正确地得到激发态的阻尼才能确定第二个峰。本文计算了高分子中电子-声子相互作用所引起的激发阻尼,它随激发态而变化。根据此种激发阻尼求得的三次谐波产生谱,其理论计算与实验数据很好地符合。

The third harmonic generation spectrum (THG) of trans-polyacetylene exhibits two peaks at 0.6eV and 0.9 eV respectively. None of the existing theories can give a quantitatively satis-factory interpretation. By considering properly the excitation-dependent damping, we can get the second peak at 0.9eV. The damping of excited states that we depict in this paper due to electron-phonon interaction of polymer varies with the excited states. According to this dam-ping, the theoretical results of THG agree with the observed spectrum very well.