Lopes Thiago O, Machado Daniel F Scalabrini, Risko Chad, Brédas Jean-Luc, de Oliveira Heibbe C B
Laboratório de Estrutura Eletrônica e Dinâmica Molecular (LEEDMOL), Institute of Chemistry , University of Brasília , Campus Darcy Ribeiro , Brasília , Brazil.
Department of Chemistry and Center for Applied Energy Research , University of Kentucky , Lexington , Kentucky 40506-0055 , United States.
J Phys Chem Lett. 2018 Mar 15;9(6):1377-1383. doi: 10.1021/acs.jpclett.8b00478. Epub 2018 Mar 6.
Well-defined structure-property relationships offer a conceptual basis to afford a priori design principles to develop novel π-conjugated molecular and polymer materials for nonlinear optical (NLO) applications. Here, we introduce the bond ellipticity alternation (BEA) as a robust parameter to assess the NLO characteristics of organic chromophores and illustrate its effectiveness in the case of streptocyanines. BEA is based on the symmetry of the electron density, a physical observable that can be determined from experimental X-ray electron densities or from quantum-chemical calculations. Through comparisons to the well-established bond-length alternation and π-bond order alternation parameters, we demonstrate the generality of BEA to foreshadow NLO characteristics and underline that, in the case of large electric fields, BEA is a more reliable descriptor. Hence, this study introduces BEA as a prominent descriptor of organic chromophores of interest for NLO applications.
明确的结构-性质关系为开发用于非线性光学（NLO）应用的新型π共轭分子和聚合物材料提供先验设计原则提供了概念基础。在此，我们引入键椭圆率交替（BEA）作为评估有机发色团NLO特性的有力参数，并在链花青染料的情况下说明其有效性。BEA基于电子密度的对称性，这是一个可从实验X射线电子密度或量子化学计算中确定的物理可观测量。通过与已确立的键长交替和π键序交替参数进行比较，我们证明了BEA预示NLO特性的普遍性，并强调在强电场情况下，BEA是一个更可靠的描述符。因此，本研究引入BEA作为NLO应用中感兴趣的有机发色团的突出描述符。
