Verbiest T, Clays K, Persoons A, Meyers F, Brédas J L
Opt Lett. 1993 Apr 1;18(7):525-7. doi: 10.1364/ol.18.000525.
The first observation to our knowledge of a second-order nonlinear optical effect in a nonpolar molecular ion is reported. Hyper-Rayleigh scattering was observed from aqueous and organic solutions of the tricyanomethanide ion C(CN)(3). Because of the absence of a dipole moment and the presence of a charge in this planar, nonpolar, but highly polarizable molecular anion with D(3h) symmetry, no electric-field-induced second-harmonic-generation experiments are possible. The experimental values for the first hyperpolarizability beta(xxx) [(7 +/- 1.5) x 10(-30) esu, independent of the solvent] are in good agreement with the results from quantum-chemical calculations.
据我们所知，首次报道了在非极性分子离子中观察到的二阶非线性光学效应。在三氰甲烷离子[C(CN)(3)]⁻的水溶液和有机溶液中观察到了超瑞利散射。由于这种具有D(3h)对称性的平面、非极性但高度可极化的分子阴离子没有偶极矩且带有电荷，因此无法进行电场诱导二次谐波产生实验。第一超极化率β(xxx)的实验值[(7±1.5)×10⁻³⁰ esu，与溶剂无关]与量子化学计算结果高度吻合。
