Negatively charged xenon atoms and clusters

Abstract

Experimental evidence is presented, for the first time, that ${\mathrm{Xe}}_{\mathrm{N}}^{\mathrm{\ensuremath{-}}}$, N\ensuremath{\ge}1, atoms and clusters have a lifetime of about ${10}^{\mathrm{\ensuremath{-}}4}$ s or longer. It is discussed whether the negatively charged xenon atoms and small clusters are in the ground or in an electronically excited, metastable state. Ground-state ${\mathrm{Xe}}_{\mathrm{N}}^{\mathrm{\ensuremath{-}}}$ clusters are stable if N\ensuremath{\ge}6 and probably down to N=2. Structure in the mass spectra correlates well with calculated binding energies.