Janoš Jiří, Slavíček Petr, Curchod Basile F E
Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, Prague 6, 166 28, Czech Republic.
Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom.
J Phys Chem Lett. 2024 Oct 24;15(42):10614-10622. doi: 10.1021/acs.jpclett.4c02549. Epub 2024 Oct 15.
Over the last decades, theoretical photochemistry has produced multiple techniques to simulate the nonadiabatic dynamics of molecules. Surprisingly, much less effort has been devoted to adequately describing the first step of a photochemical or photophysical process: photoexcitation. Here, we propose a formalism to include the effect of a laser pulse in trajectory-based nonadiabatic dynamics at the level of the initial conditions, with no additional cost. The promoted density approach (PDA) decouples the excitation from the nonadiabatic dynamics by defining a new set of initial conditions, which include an excitation time. PDA with surface hopping leads to nonadiabatic dynamics simulations in excellent agreement with quantum dynamics using an explicit laser pulse and highlights the strong impact of a laser pulse on the resulting photodynamics and the limits of the (sudden) vertical excitation. Combining PDA with trajectory-based nonadiabatic methods is possible for any arbitrary-sized molecules using a code provided in this work.
在过去几十年中，理论光化学已产生多种技术来模拟分子的非绝热动力学。令人惊讶的是，在充分描述光化学或光物理过程的第一步：光激发方面所做的工作要少得多。在此，我们提出一种形式主义方法，以便在初始条件层面将激光脉冲的影响纳入基于轨迹的非绝热动力学中，且无需额外成本。推广密度方法（PDA）通过定义一组新的初始条件（包括激发时间），将激发与非绝热动力学解耦。带有表面跳跃的PDA能够进行非绝热动力学模拟，其结果与使用显式激光脉冲的量子动力学结果高度吻合，并突出了激光脉冲对最终光动力学的强烈影响以及（突然）垂直激发的局限性。利用本文提供的代码，对于任意大小的分子，都可以将PDA与基于轨迹的非绝热方法相结合。
