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.

分子暴露于阿秒极紫外 （XUV） 脉冲为研究耦合电子-核动力学的早期阶段提供了一个独特的机会，其中不同自由度所起的作用超出了标准的化学直觉。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）中的快速电离启动的电荷转移过程的第一步。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，可以对该过程进行时间分辨测量。我们表明，协同的核和电子运动在亚 10 fs 的时间尺度上驱动来自供体组的电子转移。随后是低于 30 fs 的弛豫过程，因为在分子阳离子的激发电子状态中探测连续扩散的核波包。这些发现阐明了电子-核耦合在供体-π-受体系统中响应光离子化所发挥的作用。