Coulomb explosion velocity-map imaging is a new and potentially universal probe for gas-phase chemical dynamics studies, capable of yielding direct information on (time-evolving) molecular structure. The approach relies on a detailed understanding of the mapping between the initial atomic positions within the molecular structure of interest and the final velocities of the fragments formed via Coulomb explosion. Comprehensive on-the-fly ab initio trajectory studies of the Coulomb explosion dynamics are presented for two prototypical small molecules, formyl chloride and cis-1,2-dichloroethene, in order to explore conditions under which reliable structural information can be extracted from fragment velocity-map images. It is shown that for low parent ion charge states, the mapping from initial atomic positions to final fragment velocities is complex and very sensitive to the parent ion charge state as well as many other experimental and simulation parameters. For high-charge states, however, the mapping is much more straightforward and dominated by Coulombic interactions (moderated, if appropriate, by the requirements of overall spin conservation). This study proposes minimum requirements for the high-charge regime, highlights the need to work in this regime in order to obtain robust structural information from fragment velocity-map images, and suggests how quantitative structural information may be extracted from experimental data.

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库仑爆炸成像用于气相分子结构测定：Anab初始轨迹模拟研究

库仑爆炸速度图成像是一种用于气相化学动力学研究的新型且可能通用的探针，能够产生有关（随时间变化的）分子结构的直接信息。该方法依赖于对目标分子结构内的初始原子位置与通过库仑爆炸形成的片段的最终速度之间的映射的详细理解。全面上即时从头库仑爆炸动力学呈现了两个典型的小分子，甲酰氯和轨迹研究顺-1,2-二氯乙烯，以探索可从片段速度图图像中提取可靠结构信息的条件。结果表明，对于低的母体离子电荷状态，从初始原子位置到最终碎片速度的映射是复杂的，并且对母体离子电荷状态以及许多其他实验和模拟参数非常敏感。但是，对于高电荷状态，映射要简单得多，并且由库仑相互作用（如果适当，由整体自旋守恒的要求进行调节）来控制。这项研究提出了高电荷状态的最低要求，强调了在此状态下工作的必要性，以便从碎片速度图图像中获得可靠的结构信息，