School of Physics and Optoelectronic Engineering, Ludong University, Yantai 264025, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2019 May 5;214:86-94. doi: 10.1016/j.saa.2019.02.001. Epub 2019 Feb 5.
Nonadiabatic dynamics of a nonplanar green fluorescent protein (GFP) chromophore derivative was examined theoretically by trajectory surface hopping approach at the CASSCF level based on Zhu-Nakamura theory. The geometry optimizations show that there are four ground-state minima and four conical intersections between the ground (S) and first excited (S) states. Four S-state minima were found at a perpendicularly twisted conformation around the imidazolinone-bridged bond. Upon excitation to S state, the main decay pathways of four isomers involve different S/S potential energy surface conical intersections. The dominant excited-state relaxation mechanism of this GFP chromophore derivative is the twists of two bridging bonds and the methyl group in the bridge combined with the pyramidalization character of the central carbon atom. Further twists of two bridging bonds and the methyl group occur sequentially in the S state. It is worth to mention that the special volume-conserving motion of this molecule is attributed to twists of two bridging bonds in the same direction during the whole photoisomerization processes. The theoretical investigation presented herein provides important insights into the volume-conserving photoisomerization mechanisms of a nonplanar GFP chromophore derivative. We believe that the present work can benefit the design of the photochromic molecule devices in confined media.
非绝热动力学的非平面绿色荧光蛋白 (GFP) 发色团衍生物通过轨迹表面跳跃方法在 CASSCF 水平上进行了理论研究，基于 Zhu-Nakamura 理论。几何优化表明，在基态 (S) 和第一激发态 (S) 之间存在四个基态最小值和四个锥形交叉。在围绕咪唑啉酮桥键的垂直扭曲构象中发现了四个 S 态最小值。激发到 S 态后，四个异构体的主要衰减途径涉及不同的 S/S 势能面锥形交叉。这种 GFP 发色团衍生物的主要激发态弛豫机制是两个桥键和桥中的甲基的扭转以及中心碳原子的金字塔化特征。在 S 态中，两个桥键和甲基的进一步扭转是顺序发生的。值得一提的是，这种分子的特殊体积守恒运动归因于在整个光致异构化过程中两个桥键沿相同方向的扭转。本文的理论研究为非平面 GFP 发色团衍生物的体积守恒光致异构化机制提供了重要的见解。我们相信，目前的工作可以有益于受限介质中光致变色分子器件的设计。
