text: Radiation is produced owing to the spontaneous transition of an excimer molecule from an excited electronic state to the ground state. Excimer and exciplex molecules are not long-living formations. They rapidly decompose, typically within a few nanoseconds, releasing their excitation energy in the form of a UV photon:
  : emission by an excimer molecule:
  : emission by an exciplex molecule:
  where Rg* is an excimer molecule, RgX* is an exciplex molecule, Rg is an atom of rare gas, and X is an atom of halogen.