We describe the results of experiments and simulations performed with the aim of extending photoelectron spectroscopy with intense laser pulses to the case of molecular compounds. Dimer frame photoelectron angular distributions generated by double ionization of ${\mathrm{N}}_2-{\mathrm{N}}_2$ and ${\mathrm{N}}_2-{\mathrm{O}}_2$ van der Waals dimers with ultrashort, intense laser pulses are measured using four-body coincidence imaging with a reaction microscope. To study the influence of the first-generated molecular ion on the ionization behavior of the remaining neutral molecule we employ a two-pulse sequence comprising of a linearly polarized and a delayed elliptically polarized laser pulse that allows distinguishing the two ionization steps. By analysis of the obtained electron momentum distributions we show that scattering of the photoelectron on the neighboring molecular potential leads to a deformation and rotation of the photoelectron angular distribution as compared to that measured for an isolated molecule. Based on this result we demonstrate that the electron momentum space in the dimer case can be separated, allowing us to extract information about the ionization pathway from the photoelectron angular distributions. Our work, when implemented with a variable pulse delay, opens up the possibility of investigating light-induced electronic dynamics in molecular dimers using angularly resolved photoelectron spectroscopy with intense laser pulses.

中文翻译：

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探索两个延迟强激光脉冲从分子二聚体发出的光电子角分布

我们描述了实验和模拟的结果，其目的是将具有强激光脉冲的光电子能谱扩展到分子化合物的情况。二次离子化产生的二聚体框架光电子角分布。${\mathrm{ñ}}_2-{\mathrm{ñ}}_2$ 和 ${\mathrm{ñ}}_2-{\mathrm{Ø}}_2$具有超短，强激光脉冲的范德华二聚体使用反应显微镜使用四体重合成像进行测量。为了研究第一代分子离子对其余中性分子电离行为的影响，我们采用了由线性极化和延迟椭圆极化激光脉冲组成的两脉冲序列，可以区分两个电离步骤。通过对获得的电子动量分布的分析，我们发现，与对分离的分子所测量的结果相比，光电子在相邻分子电势上的散射导致光电子角分布的变形和旋转。基于此结果，我们证明了二聚体情况下的电子动量空间可以分离，使我们能够从光电子角分布中提取有关电离途径的信息。我们的工作在实现可变脉冲延迟的情况下，开辟了使用具有强激光脉冲的角度分辨光电子能谱研究分子二聚体中光诱导的电子动力学的可能性。