Treiber Leonhard, Kanya Reika, Kitzler-Zeiler Markus, Koch Markus
Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, 8010Graz, Austria.
Department of Chemistry, Faculty of Science, Tokyo Metropolitan University, 1-1 minami-Osawa, Hachioji-shi, Tokyo192-0397, Japan.
J Phys Chem A. 2022 Nov 17;126(45):8380-8387. doi: 10.1021/acs.jpca.2c05410. Epub 2022 Nov 3.
Laser-assisted electron scattering (LAES) is a fundamental three body interaction process that enables energy transfer between electrons and photons in the presence of matter. Here, we focus on the multiscattering regime of electrons generated by above-threshold ionization (ATI) of In atoms inside a high-density nanostructure, helium nanodroplets (He) of ∼40 Å radius. The stochastic nature of the multiscattering regime results in photoelectron spectra independent of laser polarization. Numerical simulations via tunnel-type ionization followed by applying the Kroll-Watson approximation for LAES are in agreement with experimental spectra and yield a mechanistic description of electron generation and the LAES energy modulation processes. We find a negligible influence of the electron start position inside the helium droplet on the simulated electron energy spectrum. Further, our simulations shine light on the interplay of electron time of birth, number of LAES gain/loss events, and final kinetic energy; early ionization leads to the largest number of scattering events and thereby the highest electron kinetic energy.
激光辅助电子散射（LAES）是一种基本的三体相互作用过程，它能在有物质存在的情况下实现电子与光子之间的能量转移。在此，我们聚焦于由高密度纳米结构（半径约为40 Å的氦纳米液滴（He））内铟原子的阈上电离（ATI）所产生的电子的多次散射区域。多次散射区域的随机性导致光电子能谱与激光偏振无关。通过隧穿型电离进行数值模拟，随后对LAES应用克罗尔 - 沃森近似，这与实验能谱相符，并给出了电子产生和LAES能量调制过程的机理描述。我们发现氦液滴内电子起始位置对模拟电子能谱的影响可忽略不计。此外，我们的模拟揭示了电子产生时间、LAES增益/损失事件数量与最终动能之间的相互作用；早期电离会导致最多的散射事件，从而产生最高的电子动能。
