Autoionization dynamics of helium nanodroplets resonantly excited by intense XUV laser pulses. (17th August 2020)

• Record Type: Journal Article
• Authors: Ovcharenko, Y; LaForge, A C; Langbehn, B; Plekan, O; Cucini, R; Finetti, P; O'Keeffe, P; Iablonskyi, D; Nishiyama, T; Ueda, K; Piseri, P; Di Fraia, M; Richter, R; Coreno, M; Callegari, C; Prince, K C; Stienkemeier, F; Möller, T; Mudrich, M
• Is Part Of: New journal of physics. Volume 22:Number 8(2020:Aug.)
• Publication Date: 2020-08-17
• Subjects: He nanodroplets -- interatomic Coulombic decay -- collective autoionization -- nanoplasma; Physics -- Periodicals; Physics; Periodicals; 530.05
• DOI: 10.1088/1367-2630/ab9554
• Languages: English
• ISSNs: 1367-2630

Abstract

Abstract: The ionization dynamics of helium droplets irradiated by intense, femtosecond extreme ultraviolet (XUV) pulses is investigated in detail by photoelectron spectroscopy. Helium droplets are resonantly excited to atomic-like 2p states with a photon energy of 21.5 eV and autoionize by interatomic Coulombic decay (ICD). A complex evolution of the electron spectra as a function of droplet size (250 to 10 6 He atoms per droplet) and XUV intensity (10 9 –10 12 W cm −2 ) is observed, ranging from narrow atomic-like peaks that are due to binary autoionization, to an unstructured feature characteristic of electron emission from a nanoplasma. The experimental results are analyzed and interpreted with the help of a numerical simulation based on rate equations taking into account all relevant processes—multi-step ionization, electronic relaxation, ICD, secondary inelastic collisions, desorption of electronically excited atoms, and collective autoionization (CAI).