Sokolovskii Ilia, Morozov Dmitry, Groenhof Gerrit
Nanoscience Center and Department of Chemistry, University of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland.
J Chem Phys. 2024 Oct 7;161(13). doi: 10.1063/5.0227515.
Collective strong coupling of many molecules to the confined light modes of an optical resonator can influence the photochemistry of these molecules, but the origin of this effect is not yet fully understood. To provide atomistic insights, several approaches have been developed based on quantum chemistry or molecular dynamics methods. However, most of these methods rely on coupling a few molecules (or sometimes only one) to a single cavity mode. To reach the strong coupling regime with such a small number of molecules, much larger vacuum field strengths are employed than in experiments. To keep the vacuum field realistic and avoid potential artefacts, the number of coupled molecules should be significantly increased instead, but that is not always possible due to restrictions on computational hardware and software. To overcome this barrier and model the dynamics of an arbitrarily large ensemble of molecules coupled to realistic cavity fields in atomistic molecular dynamics simulations, we propose to coarse-grain subsets of molecules into one or more effective supermolecules with an enhanced dipole moment and concerted dynamics. To verify the validity of the proposed multiscale model, we performed simulations in which we investigated how the number of molecules that are coupled to the cavity affects excited-state intra-molecular proton transfer, polariton relaxation, and exciton transport.
许多分子与光学谐振器的受限光模式的集体强耦合会影响这些分子的光化学，但这种效应的起源尚未完全理解。为了提供原子层面的见解，已经基于量子化学或分子动力学方法开发了几种方法。然而，这些方法大多依赖于将少数几个分子（有时甚至只有一个）耦合到单个腔模。为了用如此少量的分子达到强耦合状态，所采用的真空场强度比实验中的要大得多。为了使真空场符合实际并避免潜在的人为因素，反而应该显著增加耦合分子的数量，但由于计算硬件和软件的限制，这并不总是可行的。为了克服这一障碍，并在原子分子动力学模拟中对与实际腔场耦合的任意大量分子集合的动力学进行建模，我们建议将分子子集粗粒化为一个或多个具有增强偶极矩和协同动力学的有效超分子。为了验证所提出的多尺度模型的有效性，我们进行了模拟，研究了与腔耦合的分子数量如何影响激发态分子内质子转移、极化子弛豫和激子传输。
