Model for Photoinduced Bending of Slender Molecular Crystals
Model for Photoinduced Bending of Slender Molecular Crystals
复制标题
DOI：
10.1021/ja4101497
复制
发表时间：
2014-02-19
影响因子：
15
通讯作者：
Naumov, Pance
中科院分区：
文献类型：
--
作者：
Nath, Naba K.;Pejov, Ljupco;Naumov, Pance
越来越多的人意识到，细长的光反应单晶的光致弯曲是令人惊讶的常见现象，这促使研究人员控制晶体的运动来驱动。然而，新的机械响应晶体的报道速度比它们的定量光物理表征更快；决定机械响应的可测量参数和分子尺度因素的定量识别尚未建立。本文给出了宏观单晶准静态和含时光致弯曲的简单数学描述。这个动力学模型超越了将弯曲的晶体近似处理为简单的复合双层的范围。它包括激发态衰减的替代路径，并通过考虑产物/反应物比中的空间梯度来更准确地描述弯曲。在上述模型的约束下，分析了一种新的光敏偶氮染料分散红1(DR1)的晶型(空间群P2(1)/n)。晶体弯曲动力学取决于内在因素(晶体尺寸)和外部因素(激发时间、方向和强度)。
The growing realization that photoinduced bending of slender photoreactive single crystals is surprisingly common has inspired researchers to control crystal motility for actuation. However, new mechanically responsive crystals are reported at a greater rate than their quantitative photophysical characterization; a quantitative identification of measurable parameters and molecular-scale factors that determine the mechanical response has yet to be established. Herein, a simple mathematical description of the quasi-static and time-dependent photoinduced bending of macroscopic single crystals is provided. This kinetic model goes beyond the approximate treatment of a bending crystal as a simple composite bilayer. It includes alternative pathways for excited-state decay and provides a more accurate description of the bending by accounting for the spatial gradient in the product/reactant ratio. A new crystal form (space group P2(1)/n) of the photoresponsive azo-dye Disperse Red 1 (DR1) is analyzed within the constraints of the aforementioned model. The crystal bending kinetics depends on intrinsic factors (crystal size) and external factors (excitation time, direction, and intensity).