Cavity-enabled enhancement of ultrafast intramolecular vibrational redistribution over pseudorotation
Cavity-enabled enhancement of ultrafast intramolecular vibrational redistribution over pseudorotation
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DOI：
10.1126/science.add0276
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发表时间：
2022-11-18
期刊：
影响因子：
56.9
通讯作者：
Xiong, Wei
中科院分区：
文献类型：
--
作者：
Chen, Teng-Teng;Du, Matthew;Xiong, Wei
分子振动和微腔光子之间的振动强耦合（VSC）产生一些极化子（光物质模式）和许多暗模式（具有可忽略的光子特征）。尽管据报道 VSC 可以改变热激活化学反应，但其机制仍然不透明。为了阐明这个问题，我们跟踪了 VSC 下五羰基铁 [Fe(CO)(5)] 中简单单分子振动能量交换的超快动力学，结果显示了两个竞争通道：赝旋转和分子内振动能量重新分配 (IVR)。我们发现，在极化子激发下，能量交换总体加速，IVR 变快，赝旋转减慢。然而，与腔外的激发相比，暗模式激发显示的动力学没有变化，以赝旋转为主。因此，尽管围绕热激活 VSC 改性化学存在争议，但我们的工作表明 VSC 确实可以通过极化激元的非平衡制备来改变化学。
Vibrational strong coupling (VSC) between molecular vibrations and microcavity photons yields a few polaritons (light-matter modes) and many dark modes (with negligible photonic character). Although VSC is reported to alter thermally activated chemical reactions, its mechanisms remain opaque. To elucidate this problem, we followed ultrafast dynamics of a simple unimolecular vibrational energy exchange in iron pentacarbonyl [Fe(CO)(5)] under VSC, which showed two competing channels: pseudorotation and intramolecular vibrational-energy redistribution (IVR). We found that under polariton excitation, energy exchange was overall accelerated, with IVR becoming faster and pseudorotation being slowed down. However, dark-mode excitation revealed unchanged dynamics compared with those outside of the cavity, with pseudorotation dominating. Thus, despite controversies around thermally activated VSC modified chemistry, our work shows that VSC can indeed alter chemistry through a nonequilibrium preparation of polaritons.