溶致变色法测定Schiff碱类化合物非线性二阶极化率张量分量β_(xxx)和估算二阶极化率向量分量β_x

Determination of the Second-rank Polarizabilities Tensor β_(xxx) and Estimation of Second-ordor Polarizabilities Vector β_x of Schiff Base Compounds by Solvatochromic Method

提出了一个以二能级模型为基础,结合溶致变色法计算非线性光学分子二阶极化率向量分量β_x的新方法.使用溶致变色法测定了新的Schiff碱化合物的二阶极化率张量分量β_(xxx),并对其非线性光学特性进行了评估.

A semiemperical equation of Inβx, hence βx bases on two-level model was proposed with a good linear relationship with experimental data for the nonlinear optical molecules with donar-acceptor groups:Inβx =x1 +x2Inμeg+x3In(μe -μg) + x4Inω2eg/(ω2eg-ω2)(ω2eg-4ω2)where x1 = 81.90, x2 = 1.753, x3 = 0.5678 and x4= 1.21.The second-rank polarizabilitys tensor βxxx of Schiff base compounds synthesized in our laboratory was determined by solvatochromic method. The second-order polarizabilitys vector βx from solvatochromic data were estimated by our semiemperical equation. Solvatochromic method provides chemists a simple and exact enough method to determine both βxxx and βx for the nonlinear optical materials, especially for the compounds which has no SHG signal due to its centrosymmetry space group. The experimental data for the schiff base compounds showed large βx which was discussed on the bases of substituent group and solvent effect in different molecules.