Ultrafast electronic relaxation pathways of the molecular photoswitch quadricyclane.
Ultrafast electronic relaxation pathways of the molecular photoswitch quadricyclane.
复制标题
分子光开关四环烷的超快电子弛豫路径。
DOI：
10.1038/s41557-023-01420-w
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发表时间：
2024
期刊：
影响因子：
21.8
通讯作者：
Borne KD
中科院分区：
文献类型：
--
作者：
Borne KD
光诱导的降冰片二烯和四环烷分子异构体之间的超快速切换可以可逆地储存和释放大量的化学能。以前的工作在紫外光激发下观察到了这两种异构体的超快分子动力学特征，但在实验上并不能完全跟随电子驰豫回到基态。在这里，我们用时间分辨的气相极紫外光电子能谱结合非绝热分子动力学模拟研究了四环烷在紫外光(201 纳米)激发后的电子弛豫。我们确定了两条相互竞争的途径，通过这些途径，电子激发的四环分子松弛到电子基态。快路径(<；100 飞秒)的区别在于有效地耦合到价电子态，而慢路径涉及跨越里德堡态的初始运动，需要数百飞秒。这两条途径都促进了两个异构体之间的相互转化，尽管在不同的时间尺度上，我们预测降冰片二烯/四环烷产物在返回电子基态后立即的支化比约为3：2。
The light-induced ultrafast switching between molecular isomers norbornadiene and quadricyclane can reversibly store and release a substantial amount of chemical energy. Prior work observed signatures of ultrafast molecular dynamics in both isomers upon ultraviolet excitation but could not follow the electronic relaxation all the way back to the ground state experimentally. Here we study the electronic relaxation of quadricyclane after exciting in the ultraviolet (201 nanometres) using time-resolved gas-phase extreme ultraviolet photoelectron spectroscopy combined with non-adiabatic molecular dynamics simulations. We identify two competing pathways by which electronically excited quadricyclane molecules relax to the electronic ground state. The fast pathway (<100 femtoseconds) is distinguished by effective coupling to valence electronic states, while the slow pathway involves initial motions across Rydberg states and takes several hundred femtoseconds. Both pathways facilitate interconversion between the two isomers, albeit on different timescales, and we predict that the branching ratio of norbornadiene/quadricyclane products immediately after returning to the electronic ground state is approximately 3:2.