Controlling the nonadiabatic electron-transfer reaction rate through molecular-vibration polaritons in the ultrastrong coupling regime
Controlling the nonadiabatic electron-transfer reaction rate through molecular-vibration polaritons in the ultrastrong coupling regime
复制标题
在超强耦合状态下通过分子振动极化子控制非绝热电子转移反应速率
DOI：
10.1038/s41598-020-62899-8
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发表时间：
2020
影响因子：
4.6
通讯作者：
Akihito Ishizaki
中科院分区：
文献类型：
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作者：
Nguyen Thanh Phuc;Pham Quang Trung;Akihito Ishizaki
最近的实验表明，通过将核振动模式与光学腔的单模强耦合，可以改变化学反应速率，无论是增加还是减少。在这里，我们研究了电子转移反应的速率如何取决于超强耦合状态下的分子-腔耦合，其中耦合强度的大小与振动频率和腔频率相当。我们发现了决定反应速率变化的两个主要因素：分子加腔混合系统基态中分子振动的基态和激发态的耦合和混合引起的能级的相对移动，通过这种变化改变了过渡的初始状态和最终状态之间的弗兰克-康登因子。如果反应物和产物状态的分子-腔耦合强度彼此显着不同，并导致在较宽的系统参数范围内反应速率增加，则前者是主导因素。如果反应物和产物状态的耦合强度和能级彼此接近，则后者占主导地位，并导致反应速率降低。然而，由于所得极化子的集体性质，分子振动状态的混合对反应速率的影响在包含大量分子的系统中受到抑制，因此应该在包含少量分子的系统中观察到。相反，能级相对移动的影响应该基本上与耦合到腔的分子数量无关。
Recent experiments showed that the chemical reaction rate is modified, either increased or decreased, by strongly coupling a nuclear vibration mode to the single mode of an optical cavity. Herein we investigate how the rate of an electron-transfer reaction depends on the molecule-cavity coupling in the ultrastrong coupling regime, where the coupling strength is comparable in magnitude with both the vibrational and the cavity frequencies. We found two main factors that determine the modification of the reaction rate: the relative shifts of the energy levels induced by the coupling and the mixing of the ground and excited states of molecular vibration in the ground state of the hybrid molecule-plus-cavity system through which the Franck-Condon factor between the initial and final states of the transition is altered. The former is the dominant factor if the molecule-cavity coupling strengths for the reactant and product states differ significantly from each other and gives rise to an increase in the reaction rate over a wide range of system’s parameters. The latter dominates if the coupling strengths and energy levels of the reactant and product states are close to each other and it leads to a decrease in the reaction rate. The effect of the mixing of molecular vibrational states on the reaction rate is, however, suppressed in a system containing a large number of molecules due to the collective nature of the resulting polariton, and thus should be observed in a system containing a small number of molecules. In contrast, the effect of the relative shifts of the energy levels should be essentially independent of the number of molecules coupled to the cavity.