Intrinsic luminescence and radiation defects in scapolite

The intrinsic and impurity luminescence in natural meionite Ca-4[Al6Si6O24]CO3 (scapolite) is investigated. Several luminescence bands in the region of 3-5 eV are identified, with excitation occurring in the 6-8 eV range. These bands are associated with different complexes within the meionite structure. Additionally, impurity luminescence at approximately 2.25 eV is observed, which is attributed to Mn2+ ions. This luminescence is not only excited through intracenter d-d excitation but also in the region of excitation of intrinsic luminescence related to carbonate complexes. The origin of the blue coloration in the studied meionite is also discussed, which is attributed to the formation of CO3 center dot- anion radicals after irradiation. These complexes are also detected in the Raman spectrum.