Cavity-altered thermal isomerization rates and dynamical resonant localization in vibro-polaritonic chemistry
Cavity-altered thermal isomerization rates and dynamical resonant localization in vibro-polaritonic chemistry
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DOI：
10.1063/5.0076434
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发表时间：
2022-04-21
影响因子：
4.4
通讯作者：
Saalfrank, Peter
中科院分区：
文献类型：
--
作者：
Fischer, Eric W.;Anders, Janet;Saalfrank, Peter
实验证明，与在“普通”反应条件下观察到的速率相比，嵌入微流体光学腔中的分子的反应速率被改变。然而，光腔模式与分子振动的强耦合如何影响反应性以及共振行为如何出现的精确机制仍然存在争议。在目前的工作中，我们从热模型反应的角度来探讨这些机制问题，氨的反转沿着伞模式，在存在的单腔模式的变化的频率和耦合强度。结合量子力学和过渡态理论速率计算的相关腔Born-Oppenheimer势能面的拓扑分析揭示了两种量子效应，导致与实验定性一致的减速反应速率：- 在过渡态垂直于反应路径的量子化模式的硬化，这减少了可热接近的反应通道的数量，以及势垒区的加宽，这减弱了隧穿。我们发现这两种效应在波动的环境中是非常强大的，导致潜在的参数，如势垒高度的统计变化。此外，通过求解含时薛定谔方程的振动强耦合制度，我们确定了共振行为，定性与实验和早期的理论工作。后者表现为当腔频率ω（c）被调谐为与分子反应物频率共振时降低的反应概率。我们发现这种效应是基于反应物中的振动极化激元波包的动力学局域化。由AIP Publishing独家授权出版。
It has been experimentally demonstrated that reaction rates for molecules embedded in microfluidic optical cavities are altered when compared to rates observed under "ordinary" reaction conditions. However, precise mechanisms of how strong coupling of an optical cavity mode to molecular vibrations affects the reactivity and how resonance behavior emerges are still under dispute. In the present work, we approach these mechanistic issues from the perspective of a thermal model reaction, the inversion of ammonia along the umbrella mode, in the presence of a single-cavity mode of varying frequency and coupling strength. A topological analysis of the related cavity Born-Oppenheimer potential energy surface in combination with quantum mechanical and transition state theory rate calculations reveals two quantum effects, leading to decelerated reaction rates in qualitative agreement with experiments: the stiffening of quantized modes perpendicular to the reaction path at the transition state, which reduces the number of thermally accessible reaction channels, and the broadening of the barrier region, which attenuates tunneling. We find these two effects to be very robust in a fluctuating environment, causing statistical variations of potential parameters, such as the barrier height. Furthermore, by solving the time-dependent Schrodinger equation in the vibrational strong coupling regime, we identify a resonance behavior, in qualitative agreement with experimental and earlier theoretical work. The latter manifests as reduced reaction probability when the cavity frequency omega(c) is tuned resonant to a molecular reactant frequency. We find this effect to be based on the dynamical localization of the vibro-polaritonic wavepacket in the reactant well. Published under an exclusive license by AIP Publishing.