摘要
用量子化学方法计算了2H-苯并吡喃-2-酮类化合物的分子二阶非线性光学系数,研究了取代基效应、取代位置以及电子性质对分子二阶非线性光学效应的影响,并提出了标题化合物可作为性质优良的二阶非线性光学材料的设计方案。
Having calculated the molecular second-order nonlinear optical polarizabilities β of 2H-Benzopyran-2-one using the quantum chemistry method, and studied the subsitituent effects and the electronic properties, the authors find that: (1) Substitution of the 7th position in the title molecule is more effective than that of the 4th position; (2) Disubstitution can not increase the β values, some disubstituted molecular nonlinearities is even decreased; (3)The substituent effects are not obvious in these molecules, which is determined by the molecular electronic properties; (4)CH3 is a structural group and its electron donating ability is very weak; (5) The atom 0 attached to the carbonyl leads to intramolecular single-track charge transfer. According to the calculated results we suggest the approaches to design the excellent second-order NLO materials: (1) Substitution of different groups on the 4th and 7th position of the title molecules benefits the noncentrosymmetric crystal structure and therefore the second-order nonlinear optical properties; (2) Large groups substituted on the 7th position are propitious to the molecular packing in the crystal, and so the macroscopic nonlinearity of the materials; (3) To improve the transparency and the thermal stability of the materials the groups favor the hydrogen bonds should be preferentially introduced while the strong acceptors and donors should be avoided. 2H-Benzopyran-2-one is the excellent candidate compounds for the second-order NLO materials with strong NLO properties and good transparency and thermal stability, as is very important in the theoretical and applied fields.
出处
《南京晓庄学院学报》
2004年第4期28-32,共5页
Journal of Nanjing Xiaozhuang University
基金
江苏省教委自然科学基金资助项目(02KJD150005)
