变-4,4'-阿佐皮里丁的波长依赖光异构化:非adiabatic动力学模拟
Aihua Gao1, Meishan Wang1, Yanli Liu1
1School of Physics and Optoelectronic Engineering, Ludong University, Yantai 264025, China.
概括
通过使用非adiabatic动态模拟来研究4,4'-azopyridine的光异构化. 与S1状态 (3%) 相比,对S2状态的激发产生了更高的cis-同位素量子产量 (18%).
科学领域:
- 摄影化学的使用.
- 理论化学 理论化学
- 分子动力学分子动力学
背景情况:
- 4,4 - 亚索皮里丁表现出跨光异构化,这一过程对于理解分子开关和对光敏感材料至关重要.
- 之前的实验研究为量子产量值提供了背景,需要对潜在机制进行理论研究.
研究的目的:
- 为了研究4,4 -azopyridine在激发到S1和S2电子状态时的trans-cis光异构化机制.
- 阐明分子几何学和电子转换在确定 cis-同位素量子产量的作用.
主要方法:
- 采用非adiabatic动力学模拟来建模光异构化过程.
- 多参考CASSCF计算提供了必要的潜在能量表面和电子结构信息.
- 模拟了119个采样轨迹,从变异构体开始.
主要成果:
- 确定cis-异构体的量子收益率为S1激发的 (3 ± 2) %和S2激发的 (18 ± 4) %.
- 围绕中央N-N键的旋转,加上N-N-C曲,被确定为主要的光异构化机制.
- S1激发导致S1-S0沿扭转坐标过渡较早,导致较低的cis-同位素产量.
- S2激发显示了很大一部分轨迹被困在一个潜在的井里,通过扭曲的形交叉点促进内部转换,并增加了cis-同位素产量.
结论:
- 这项研究提供了对4,4 - 亚索皮里丁光异构的详细机制理解,区分了S1和S2激发的途径.
- 模拟结果与实验结果在定性上一致,验证了理论方法.
- 这些发现强调了电子状态动态和几何因素在控制光异构化结果中的重要性.
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