title: Rare-gas clusters in intense extreme-ultraviolet pulses from a high-order harmonic source.
abstract: We report evidence for two previously unidentified effects in the ionization of rare-gas clusters by intense extreme-ultraviolet pulses. First, electron spectra indicate multistep photoemission with increasing isotropy for larger clusters due to electron-atom collisions. Second, very slow (meV) electrons are interpreted as the first experimental evidence for Rydberg-like atomic state formation in the nanoplasma expansion. Only small fractions of Xe2+ ions were found, in sharp contrast to previous results recorded under comparable conditions [Murphy et al., Phys. Rev. Lett. 101, 203401 (2008).
authors.affiliation: Max-Born-Institut, Max-Born-Strasse 2A, 12489 Berlin, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Schütte
authors.affiliation: Institute of Physics, University of Rostock, Universitäsplatz 3, 18051 Rostock, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Arbeiter
authors.affiliation: Institute of Physics, University of Rostock, Universitäsplatz 3, 18051 Rostock, Germany.
authors.forename: Th
authors.initials: T
authors.lastname: Fennel
authors.affiliation: Max-Born-Institut, Max-Born-Strasse 2A, 12489 Berlin, Germany.
authors.forename: M J J
authors.initials: MJ
authors.lastname: Vrakking
authors.affiliation: Max-Born-Institut, Max-Born-Strasse 2A, 12489 Berlin, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Rouzée