Title: Reaction Nanoscopy of Ion Emission from Sub-wavelength Propanediol Droplets Show Chinese title

Title: 离子从亚波长丙二醇液滴中的发射反应显微术

Abstract: Droplets provide unique opportunities for the investigation of laser-induced surface chemistry. Chemical reactions on the surface of charged droplets are ubiquitous in nature and can provide critical insight into more efficient processes for industrial chemical production. Here, we demonstrate the application of the reaction nanoscopy technique to strong-field ionized nanodroplets of propanediol (PDO). The technique's sensitivity to the near-field around the droplet allows for the in-situ characterization of the average droplet size and charge. The use of ultrashort laser pulses enables control of the amount of surface charge by the laser intensity. Moreover, we demonstrate the surface chemical sensitivity of reaction nanoscopy by comparing droplets of the isomers 1,2-PDO and 1,3-PDO in their ion emission and fragmentation channels. Referencing the ion yields to gas-phase data, we find an enhanced production of methyl cations from droplets of the 1,2-PDO isomer. Density functional theory simulations support that this enhancement is due to the alignment of 1,2-PDO molecules on the surface. The results pave the way towards spatio-temporal observations of charge dynamics and surface reactions on droplets in pump-probe studies. Show Chinese abstract

Abstract: 液滴为研究激光诱导的表面化学提供了独特的机会。 带电液滴表面的化学反应在自然界中无处不在，并可以为工业化学生产更高效的过程提供关键见解。 在这里，我们展示了反应显微技术在强场电离的丙二醇（PDO）纳米液滴中的应用。 该技术对液滴周围近场的敏感性使得能够原位表征液滴的平均尺寸和电荷。 使用超短激光脉冲可以通过激光强度控制表面电荷的数量。 此外，我们通过比较1,2-PDO和1,3-PDO异构体在离子发射和碎片化通道中的表现，展示了反应显微技术的表面化学灵敏度。 参考离子产率与气相数据，我们发现1,2-PDO异构体液滴中甲基阳离子的生成有所增强。 密度泛函理论模拟支持这种增强是由于1,2-PDO分子在表面的排列。 这些结果为在泵浦-探测研究中对液滴上的电荷动力学和表面反应进行时空观测铺平了道路。