Excitation and emission spectra of Ba+ ions in solid xenon

Excitation and emission spectra at 12 K temperature are presented for the first time for Ba+ in solid xenon. This is only the third such atomic ion studied in a solid noble gas matrix. Two groups of emission peaks, each with similar excitation spectra, photobleaching behavior and temperature dependence, are identified that may be associated with transitions from a common excited state in a particular solid xenon matrix site. Favorable conditions are found for imaging of single Ba+ ions in solid xenon, including reasonably strong emission efficiency, acceptable photobleaching and a method for overcoming background emission from the surface of the cooled sapphire window. A comparison of the new excitation spectrum of Ba+ in solid xenon with unpublished results on spectroscopy of Ba+ in liquid xenon helps confirm the identification of the latter.