Characterization of the cathodoluminescence emission of kamphaugite-(Y) and kristiansenite from Spain

Abstract

This paper reports on the cathodoluminescence (CL) emission of kamphaugite-(Y) (CaY(CO3)2(OH)·H2O) and kristiansenite [Ca2ScSn(Si2O7)(Si2O6OH)] that display very complex spectra. The carbonate sample, growing in spheres no longer than 3 mm, contains significant concentrations of REE giving rise to sharp and narrow wavebands peaked at 312, 486, 546, 574 and 626 nm. These wavebands would be, respectively, associated with the presence of Gd3+ (6P7/2 → 8S7/2 transition), Dy3+ (4F9/2 → 6H15/2), Tb3+ (5D4 → 7F5), Dy3+ (4F9/2 → 6H13/2) and Sm3+ (4G5/2 → 6H7/2). Kristiansenite, appearing as an isolated pseudo-hexagonal pyramidal crystal smaller than 600 µm, hardly has lanthanide elements and the CL emission is composed of broad wavebands peaked at 298 nm (linked to defect-sites caused by the presence of the Na-0.49%), 334 (due to oxygen vacancies and Me–O bonding defects), 422 (–O–O– type defects and/or O2− intrinsic defects), 494 (self-trapped excitons), 578 [Mn2+ giving rise to 4T2(G) → 6A1(S) transition and/or Ti4+/Sn4+ redox reactions] and 654 nm [due to Fe3+ 4T1(G) → 6A1(S) transitions].