Ultrafast laser pump-probe methods allow chemical reactions to be followed in real time, and have provided unprecedented insight into fundamental aspects of chemical reactivity. While evolution of the electronic structure of the system under study is evident from changes in the observed spectral signatures, information on rearrangement of the nuclear framework is generally obtained indirectly. Disentangling contributions to the signal arising from competing photochemical pathways can also be challenging. Here we introduce the new technique of three-dimensional covariance-map Coulomb explosion imaging, which has the potential to provide complete three-dimensional information on molecular structure and dynamics as they evolve in real time during a gas-phase chemical reaction. We present first proof-of-concept data from recent measurements on CF₃I. Our approach allows the contributions from competing fragmentation pathways to be isolated and characterised unambiguously, and is a promising route to enabling the recording of ‘molecular movies’ for a wide variety of gas-phase chemical processes.

超快激光泵浦探测方法允许实时跟踪化学反应，并提供了对化学反应性基本方面的前所未有的洞察力。虽然所研究系统的电子结构的演变从观察到的光谱特征的变化中显而易见，但通常间接获得有关核框架重排的信息。解开竞争性光化学途径对信号的贡献也可能具有挑战性。在这里，我们介绍了三维协方差图库仑爆炸成像新技术，该技术有可能在气相化学反应过程中实时提供分子结构和动力学的完整三维信息。我们展示了最近对 CF 测量的第一个概念验证数据₃ I. 我们的方法可以明确地分离和表征竞争性裂解途径的贡献，并且是为各种气相化学过程记录“分子电影”的有前途的途径。