The surprising nonlinear optical properties of conjugated polyyne oligomers
The surprising nonlinear optical properties of conjugated polyyne oligomers
复制标题
DOI：
10.1063/1.1707011
复制
发表时间：
2004-04-15
影响因子：
4.4
通讯作者：
Tykwinski, RR
中科院分区：
文献类型：
--
作者：
Slepkov, AD;Hegmann, FA;Tykwinski, RR
多炔类化合物是一类独特的共轭有机化合物。聚炔的三阶非线性光学响应已经得到了广泛的理论模拟，人们普遍认为聚炔的分子二次超极化率(伽马)随长度的增加应该比多烯的要小。然而，目前还没有实验证据来验证这一预测。我们已经合成了含有多达20个连续的sp型杂化碳的共轭聚炔，并测定了它们的非共振伽马值作为乙炔重复单元数(N)的函数。这些伽马值表现出与n(伽马相似吨(4.28+/-0.13))的幂规律行为，其指数既大于理论预测的多烯，也显著高于观察到的多烯或多烯。此外，没有观察到线性或非线性光学性质的饱和。(C)2004年美国物理研究所。
Polyynes represent a unique class of conjugated organic compounds. The third-order nonlinear optical response of polyynes has been extensively modeled theoretically, and it is generally believed that the increase in molecular second hyperpolarizability (gamma) as a function of length for polyynes should be lower than that for polyenes. Experimental evidence to test this prediction, however, has been absent. We have synthesized conjugated polyynes that contain up to 20 consecutive sp-hybridized carbons, and we have determined their nonresonant gamma-values as a function of the number of acetylene repeat units (n). These gamma-values demonstrate a power-law behavior versus n(gammasimilar ton(4.28+/-0.13)), with an exponent that is both larger than theoretically predicted for polyynes and substantially higher than that observed for polyenes or polyenynes. Furthermore, no saturation of the linear or nonlinear optical properties is observed. (C) 2004 American Institute of Physics.