Site-selective characterisation of electron trapping centres in relation to chemistry, structural state and mineral phases present in single crystal alkali feldspars

Feldspars are ubiquitous natural dosimeters widely used in luminescence dating. Despite decades of research, the lattice defects as well mechanisms involved production feldspars remain poorly understood. The recently developed method infrared photoluminescence (IRPL) excitation-emission spectroscopy has revealed presence two electron trapping centres emitting IRPL at 1.3 eV and 1.41 (IRPL1.3 IRPL1.41 centres), it enables detailed investigations into ground excited state energies these centres. Here we make measurements a range single crystal alkali to understand effects feldspar chemical composition, structure framework disorder on physical characteristics IRPL1.3 Measurements our sample suite reveals IR-radioluminescence (RL) emissions eV, and, for first time, 1.2 eV. Our results show that whilst centre is unaffected by M site cation occupancy, seems be linked K+ ions sites. However, no clear trends IR-RL emission signal intensities with composition samples were found. Exploring effect significant changes or centres, suggesting corresponding not located bridging O ions. Variations across whole from 2.04 2.20 2.16 2.46 centre. trap depth seem driven other factors than chemistry, degree Al3+disorder number phases present feldspar. Interestingly, IR resonance peak invariant between samples. Regarding use dating, optical resetting differs three different emissions, ∼1.41 being reset some even after 18 h solar bleaching.