1. Autoionization dynamics of He nanodroplets resonantly excited by intense XUV laser pulses
- Author
-
Ovcharenko, Y., LaForge, A., Langbehn, B., Plekan, O., Cucini, R., Finetti, P., O'Keeffe, P., Iablonskyi, D., Nishiyama, T., Ueda, K., Piseri, P., DiFraia, M., Richter, R., Coreno, M., Callegari, C., Prince, K. C., Stienkemeier, F., Moller, T., and Mudrich, M.
- Subjects
Physics - Atomic and Molecular Clusters ,14J60 (Primary) 14F05, 14J26 (Secondary) - Abstract
The ionization dynamics of helium droplets in a wide size range from 220 to 10^6 He atoms irradiated with intense femtosecond extreme ultraviolet (XUV) pulses of 10^9 {\div} 10^{12} W/cm2 power density is investigated in detail by photoelectron spectroscopy. Helium droplets are resonantly excited in the photon energy range from ~ 21 eV (corresponding to the atomic 1s2s state) up to the atomic ionization potential (IP) at ~ 25 eV. A complex evolution of the electron spectra as a function of droplet size and XUV intensity is observed, ranging from atomic-like narrow peaks 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 numerical simulations based on rate equations taking into account various processes such as multi-step ionization, interatomic Coulombic decay (ICD), secondary inelastic collisions, desorption of electronically excited atoms, collective autoionization (CAI) and further relaxation processes., Comment: 20 pages, 14 figures, 43 references
- Published
- 2019