It was shown experimentally that laser-active (F2+)H and (F2+)AH centers could be produced at significant concentrations in CO32--doped material. It was also shown that, contrary to previous reports, high optical densities of (F2+)H and (F2+)AH centers could be obtained in sulfate-doped alkali halides.

M.Diaf, K.Labaci, A.Hamaïdia, B.Rocher: Journal of Physics - Condensed Matter, 1996, 8[33], 6105-12