VACUUM ULTRAVIOLET EMISSION-SPECTRA OF THE HELIUM AND NEON ALKALI IONS IN THE RANGE BETWEEN 60-80-NM

Mixtures of neon or helium with alkali vapor were excited using an argon ion beam. The emission continua observed in the vacuum ultraviolet region between 60 and 80 nm are assigned to the decay of the ionic excimers He + K, He + Na, He + Li, Ne + Rb, Ne + K, Ne + Na, and Ne + Li into the ground state consisting of a rare gas atom and an alkali ion. The binding energies of these excimers range between 0.46 and 0.85 eV. The obtained decay energies and the fine structure splittings agree with the predictions by calculations using phenomenological potentials and by ab initio calculations. Intense emission due to the inner shell excitation of K and Rb is also observed.