| The excitation mechanisms of clusters exposed to intense laser fields in the VUV and XUV domain strongly differ from the response behavior in the near-infrared wavelength range. Whereas the heating of delocalized electrons in the nanoplasma is the dominant energy capture mechanism in optical fields, energy absorption due to the excitation of localized electrons, i.e. by the inner ionization processes itself, becomes increasingly important at high photon energy. Further, the formation of a nanoplasma is substantially delayed because of direct electron excitation into the continuum. The resulting signatures in electron energy spectra can be described by a multi-step ionization scheme. The dynamics of the energy capture, electron emission spectra, as well as nanoplasma effects are discussed based on statistical Monte-Carlo-simulations as well as moleculard dynamics results. Future prospects for XUV pump-and-probe experiments will be adressed. |
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