Excitons in rare-gas solids: Exotic or model-like?

Key results of spectroscopic experiments on excitons in rare-gas solids performed during the last three decades are summarized. They show that excitons in rare-gas solids have some unique properties due to peculiarities of the solids, like absence of acoustic phonons or huge band gap energies. On the other hand, excitons in rare-gas solids turn out to be textbook models for excitons in systems with strong exciton–lattice interaction. The substantial progress in rare-gas exciton spectroscopy was mainly due to the fact that synchrotron radiation was used as the light source, in particular for luminescence experiments. Due to some peculiar properties, excitons in rare-gas solids can serve as probes for electron–electron scattering and complex elementary excitations.