Imaging spectroscopy of rubidium atoms attached to helium nanodroplets
  Highly excited states of rubidium (Rb) atoms attached to helium (He) nanodroplets are studied by two-photon ionization spectroscopy in combination with electron and ion imaging. Photoion spectra and angular distributions are in good agreement with a pseudodiatomic model for the RbHe_N complex. Repulsive interactions in the excited states entail fast dissociation followed by ionization of free Rb atoms as well as of RbHe and RbHe_2 exciplexes. Nonresonant excitation generates Rb atoms in low-lying electronic levels by statistical evaporation-like desorption. 
L. Fechner, B. Gruener, A. Sieg, C. Callegari, F. Ancilotto, F.   Stienkemeier, and M. Mudrich
physics.atm-clus