School of Chemistry, University of Hyderabad, Hyderabad 500 046, India.
CAS Key Laboratory of Bio-Based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, CAS, Qingdao 266101, China.
J Chem Phys. 2017 Jun 7;146(21):214304. doi: 10.1063/1.4984775.
A first principles quantum dynamics study of N-H photodissociation of pyrrole on the S-πσ(A21) coupled electronic states is carried out with the aid of an optimally designed UV-laser pulse. A new photodissociation path, as compared to the conventional barrier crossing on the πσ1 state, opens up upon electronic transitions under the influence of pump-dump laser pulses, which efficiently populate both the dissociation channels. The interplay of electronic transitions due both to vibronic coupling and the laser pulse is observed in the control mechanism and discussed in detail. The proposed control mechanism seems to be robust, and not discussed in the literature so far, and is expected to trigger future experiments on the πσ1 photochemistry of molecules of chemical and biological importance. The design of the optimal pulses and their application to enhance the overall dissociation probability is carried out within the framework of optimal control theory. The quantum dynamics of the system in the presence of pulse is treated by solving the time-dependent Schrödinger equation in the semi-classical dipole approximation.
我们利用经优化设计的紫外激光脉冲，对吡咯 N-H 光解的 S-πσ(A21)耦合电子态进行了第一性原理量子动力学研究。与传统的πσ1 态上的势垒穿越相比，在泵浦-抽运激光脉冲的影响下，电子跃迁开启了一条新的光解途径，有效地填充了两个解离通道。在控制机制中观察到了由于振子耦合和激光脉冲引起的电子跃迁的相互作用，并进行了详细讨论。所提出的控制机制似乎很稳健，而且到目前为止在文献中尚未讨论过，预计将引发对具有化学和生物学重要性的分子的πσ1 光化学的未来实验。在最优控制理论的框架内，进行了最优脉冲的设计及其在提高整体解离概率方面的应用。在存在脉冲的情况下，通过在半经典偶极近似下求解含时薛定谔方程来处理系统的量子动力学。
