Correlation between the energy shell structure and geometry in metallic   nanoclusters: quasi-resonance states, isotope effect
  Metallic nanoclusters displaying electronic shell structure exhibit the special feature of a correlation between their geometry and the number of delocalized electrons . Their shape evolution can be described as a quantum oscillation between quasi-resonant states (prolate and oblate configurations) whose amplitudes depend upon the degree of shell filling. The picture explains the evolution of absorption spectra and predicts a peculiar isotope effect . 
Vladimir Kresin