Time-resolved photoionization of cluster beams at the XUV free-electron laser FERMI

XUV 自由电子激光器 FERMI 上簇束的时间分辨光电离

• 批准号: 267447508
• 负责人: Professor Dr. Frank Stienkemeier
• 金额: --
• 依托单位: Arbeitsgruppe Molekül- und Nanophysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/267447508?language=en
• 关键词: Time; resolved; photoionization; cluster; beams

The dynamics of interatomic and collective processes upon irradiation with XUV light are of fundamental interest with respect to the light-matter interaction and the distribution of excess energy in condensed systems. Highly-excited atoms decay via Interatomic Coulombic Decay (ICD) or highly-collective autoionization, if neighboring ionization potentials of neighboring atoms or molecules are lower than the excitation energy. Free electrons in clusters form plasmon resonances, which strongly enhance light absorption. Fragmentation as well as recombination of charged particles play an important role in molecular systems. Nanoparticles, such as helium droplets or molecular clusters provide ideal test-systems to study such processes, which can be triggered with intense XUV femtosecond pulses. In the current proposal, we extend the experiments and developed techniques from the first funding period to more complex systems, in particular, focusing also on water and other hydrogen bonded clusters. We will extend the time-resolved experiments of the observed ICD and double-ICD processes in doped helium droplets in the transition region from single excitations to collective effects. Furthermore, at high pulse intensities, the nanoplasma evolution in hydrogen-containing molecular clusters instead of rare-gas clusters will be investigated, thus characterizing the role of light, positive charge carriers on the plasma dynamics. This we will achieve by streaking the cluster potential in a XUV-XUV pump probe scheme. Finally, we will study XUV-induced chemical reactions in molecular clusters leading to the formation of the trihydrogen cation. The experiments will be carried out at the LDM endstation at FERMI in Trieste using a variety of time-resolved pump-probe techniques including XUV, UV, VIS and NIR radiation. Mass-resolved ion time-of-flight, as well as energy- and angular-resolved photoelectron spectroscopy including covariance methods will be applied.

在XUV光照射下的原子间和集体过程的动力学是光-物质相互作用和凝聚系统中多余能量分布的基本兴趣。如果相邻原子或分子的相邻电离势低于激发能，则高激发原子通过原子间库仑衰变（ICD）或高集体自电离而衰变。团簇中的自由电子形成等离子体共振，其强烈增强光吸收。带电粒子的碎裂和重组在分子系统中起着重要的作用。纳米粒子，如氦滴或分子簇，提供了理想的测试系统来研究这种过程，它可以被强烈的XUV飞秒脉冲触发。在目前的提案中，我们将实验和开发的技术从第一个资助期扩展到更复杂的系统，特别是还关注水和其他氢键簇。我们将扩展的时间分辨实验中观察到的ICD和双ICD过程中掺杂的氦液滴在过渡区从单一的激发集体效应。此外，在高脉冲强度下，将研究含氢分子团簇而不是稀有气体团簇中的纳米等离子体演化，从而表征光正电荷载流子对等离子体动力学的作用。这将通过在XUV-XUV泵浦探测方案中条纹化团簇势来实现。最后，我们将研究XUV诱导的分子簇中的化学反应，导致三氢阳离子的形成。这些实验将在的里雅斯特FERMI的LDM终端站进行，使用各种时间分辨泵浦探测技术，包括XUV、UV、维斯和NIR辐射。质量分辨离子飞行时间，以及能量和角度分辨光电子能谱，包括协方差方法将被应用。