Tracking multiple components of a nuclear wavepacket in photoexcited Cu(I)-phenanthroline complex using ultrafast X-ray spectroscopy
Tracking multiple components of a nuclear wavepacket in photoexcited Cu(I)-phenanthroline complex using ultrafast X-ray spectroscopy
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DOI：
10.1038/s41467-019-11499-w
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发表时间：
2019-08-09
影响因子：
16.6
通讯作者：
Penfold, Thomas J.
中科院分区：
文献类型：
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作者：
Katayama, Tetsuo;Northey, Thomas;Penfold, Thomas J.
解开电子和核自由度之间的强烈相互作用对于充分理解超快非绝热化学反应期间的激发态过程至关重要。然而，多维势能表面的复杂性意味着这仍然具有挑战性。通过使用飞秒时间分辨 X 射线吸收近边缘结构 (TR-XANES) 探测核波包，可以利用结构灵敏度来探索振动和电子弛豫过程中的能量流。然而，目前尚不清楚这种 X 射线技术可观察到的振动运动的细节程度。在此，我们使用 TR-XANES 跟踪原型 [Cu(2,9-二甲基-1,10-菲咯啉)(2)](+) 复合物的波包动力学。我们证明，对各个波包成分的敏感性可以通过探针能量进行调制，并且可以通过超出光域可观测值的亚埃分辨率来跟踪与分子呼吸模式相关的键长变化。重要的是，我们的结果揭示了最先进的 TR-XANES 如何提供对超快非绝热化学反应的更深入见解。
Disentangling the strong interplay between electronic and nuclear degrees of freedom is essential to achieve a full understanding of excited state processes during ultrafast nonadiabatic chemical reactions. However, the complexity of multi-dimensional potential energy surfaces means that this remains challenging. The energy flow during vibrational and electronic relaxation processes can be explored with structural sensitivity by probing a nuclear wavepacket using femtosecond time-resolved X-ray Absorption Near Edge Structure (TR-XANES). However, it remains unknown to what level of detail vibrational motions are observable in this X-ray technique. Herein we track the wavepacket dynamics of a prototypical [Cu(2,9-dimethyl-1,10-phenanthroline)(2)](+) complex using TR-XANES. We demonstrate that sensitivity to individual wavepacket components can be modulated by the probe energy and that the bond length change associated with molecular breathing mode can be tracked with a sub-Angstrom resolution beyond optical-domain observables. Importantly, our results reveal how state-of-the-art TR-XANES provides deeper insights of ultrafast nonadiabatic chemical reactions.