Evolution and ion kinetics of a XUV-induced nanoplasma in ammonia clusters. (18th January 2021)

• Record Type: Journal Article
• Authors: Michiels, R; LaForge, A C; Bohlen, M; Callegari, C; Clark, A; von Conta, A; Coreno, M; Di Fraia, M; Drabbels, M; Finetti, P; Huppert, M; Oliver, V; Plekan, O; Prince, K C; Stranges, S; Wörner, H J; Stienkemeier, F
• Is Part Of: Journal of physics. Volume 54:Number 2(2021)
• Publication Date: 2021-01-18
• Subjects: ammonia clusters -- nanoplasma -- femtosecond pump-probe -- photoion spectroscopy -- photoelectron spectroscopy -- covariance mapping; Atoms -- Periodicals; Molecules -- Periodicals; Optics -- Periodicals; Nuclear physics -- Periodicals; 539.6
• DOI: 10.1088/1361-6455/abcf80
• Languages: English
• ISSNs: 0953-4075

Abstract

Abstract: High-intensity extreme ultraviolet (XUV) pulses from a free-electron laser can be used to create a nanoplasma in clusters. In reference Michiels et al (2020 Phys. Chem. Chem. Phys. 22 7828–34) we investigated the formation of excited states in an XUV-induced nanoplasma in ammonia clusters. In the present article we expand our previous study with a detailed analysis of the nanoplasma evolution and ion kinetics. We use a time-delayed UV laser as probe to ionize excited states of H and H 2 + in the XUV-induced plasma. Employing covariance mapping techniques, we show that the correlated emission of protons plays an important role in the plasma dynamics. The time-dependent kinetic energy of the ions created by the probe laser is measured, revealing the charge neutralization of the cluster happens on a sub-picosecond timescale. Furthermore, we observe ro-vibrationally excited molecular hydrogen ions H 2 + * being ejected from the clusters. We rationalize our data through a qualitative model of a finite-size non-thermal plasma.