阴离子自由基TCNQ-及其铜盐CuTCNQ非线性光学性质的理论研究

摘要

Quantum chemistry methods were applied to compute and analyze the nonlinear optical (NLO) properties of the monomers and dimers for anion-radicals TCNQ- and their copper-salts. It is found that, the as values decrease as a function of the introductive Cu+ into TCNQ~ and the various positions of Cu+ have different effects on NLO coefficients. The polarizabilities of the dimers are related to their binding energies, the geometrical configurations for dimers influence the second-order NLO coefficients as well. From the frontier molecular orbit composition, the third-order NLO coefficients dependence of the charge transfer degree can be found, the overlapping between two conjugated planes also has a contribution.%采用量子化学方法计算分析了阴离子自由基TCNQ-及其铜盐CuTCNQ单体、二聚体的非线性光学(NLO)性质.结果表明,将Cu+引入TCNQ-分子,极化率值减小,Cu+的位置不同对分子NLO系数的贡献不同；二聚体分子的极化率与其结合能相关,同时分子的几何构型影响二阶NLO系数.由前线分子轨道组成得到,电子在前线分子轨道间跃迁产生的电荷转移程度决定分子三阶NLO系数的大小,二聚体分子前线分子轨道在两共轭平面间的相互重叠对分子的三阶NLO系数有一定贡献.