Matselyukh Danylo T, Rott Florian, Schnappinger Thomas, Zhang Pengju, Li Zheng, Richardson Jeremy O, de Vivie-Riedle Regina, Wörner Hans Jakob
Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, Switzerland.
Department of Chemistry, LMU Munich, Munich, Germany.
Nat Commun. 2025 Aug 5;16(1):7211. doi: 10.1038/s41467-025-62162-6.
The transfer of population between two intersecting quantum states is the most fundamental event in many dynamical processes in physics, chemistry, biology, and material science. Any two-state description of such processes requires population leaving one state to instantaneously appear in the other. We show that coupling to additional states, present in all real-world systems, can cause a measurable delay in population transfer. Using attosecond spectroscopy supported by quantum-chemical calculations, we measure a delay of 1.46 ± 0.41 fs at a charge-transfer crossing in CFI, where an electron hole moves from the fluorine atoms to iodine. Our measurements also resolve the other fundamental quantum-dynamical processes involved in the charge-transfer reaction: a vibrational rearrangement time of 9.38 ± 0.21 fs (during which the vibrational wave packet travels to the state crossing) and a population-transfer time of 2.3-2.4 fs. Our work shows that delays in population transfer readily appear in otherwise-adiabatic reactions and predicts them to be on the order of a single-femtosecond for molecular valence-state crossings. These results have implications for many research areas, such as atomic and molecular physics, charge transfer, or light harvesting.
在物理、化学、生物学和材料科学的许多动力学过程中，两个相交量子态之间的粒子转移是最基本的事件。对这类过程的任何二态描述都要求粒子从一个态离开并瞬间出现在另一个态中。我们表明，与所有现实世界系统中都存在的其他态的耦合会导致粒子转移出现可测量的延迟。利用量子化学计算支持的阿秒光谱，我们在CFI中的电荷转移交叉点测量到了1.46±0.41飞秒的延迟，在该交叉点处一个电子空穴从氟原子转移到碘原子。我们的测量还解析了电荷转移反应中涉及的其他基本量子动力学过程：振动重排时间为9.38±0.21飞秒（在此期间振动波包传播到态交叉点）以及粒子转移时间为2.3 - 2.4飞秒。我们的工作表明，粒子转移延迟很容易出现在其他情况下的绝热反应中，并预测对于分子价态交叉，延迟在单飞秒量级。这些结果对许多研究领域都有影响，例如原子与分子物理学、电荷转移或光捕获。
