The exposure of molecules to attosecond extreme-ultraviolet (XUV) pulses offers a unique opportunity to study the early stages of coupled electron–nuclear dynamics in which the role played by the different degrees of freedom is beyond standard chemical intuition. We investigate, both experimentally and theoretically, the first steps of charge-transfer processes initiated by prompt ionization in prototype donor–π–acceptor molecules, namely nitroanilines. Time-resolved measurement of this process is performed by combining attosecond XUV-pump/few-femtosecond infrared-probe spectroscopy with advanced many-body quantum chemistry calculations. We show that a concerted nuclear and electronic motion drives electron transfer from the donor group on a sub-10-fs timescale. This is followed by a sub-30-fs relaxation process due to the probing of the continuously spreading nuclear wave packet in the excited electronic states of the molecular cation. These findings shed light on the role played by electron–nuclear coupling in donor–π–acceptor systems in response to photoionization.

将分子暴露在阿秒极紫外（XUV）脉冲下为研究电子-核耦合动力学的早期阶段提供了独特的机会，其中不同自由度所发挥的作用超出了标准化学直觉。我们从实验和理论上研究了由原型供体-π-受体分子（即硝基苯胺）中的瞬时电离引发的电荷转移过程的第一步。该过程的时间分辨测量是通过将阿秒 XUV 泵/几飞秒红外探针光谱与先进的多体量子化学计算相结合来进行的。我们表明，协调一致的核运动和电子运动在亚 10 飞秒时间尺度上驱动来自供体基团的电子转移。由于在分子阳离子的激发电子态中不断扩展的核波包的探测，随后是亚 30-fs 弛豫过程。这些发现揭示了电子-核耦合在供体-π-受体系统中响应光电离所发挥的作用。