Kinetic model of energy transfer processes between low-coordinated ions on MgO by photoluminescence decay measurements

Photoluminescence decay studies of emitting species on MgO nonocubes at room temperature provide evidence of three surface species characterized by an excitation and emission wavelength couple {lambda(exc);lambda(em)}. Species A corresponds to {lambda(exc)=240 nm; lambda(em)=380nm}, whereas the couple {lambda(exc)=280nm; lambda(em)=470nm} is assigned to two species: B and B', the former is involved in energy transfer from excited state A* and the latter in direct emission from excited state B'* A simple model for energy trans-fer from species A* to B is proposed. The numerical resolution of equations corresponding to this model is in good agreement with experimental data. This method quantifies the kinetics of intrinsic emission and energy transfer processes. Lifetime values indicate that phosphorescence is taking place, and species A, B and B' are identified as edge O(4O)(2-) corner O(3C)(2-) and kink O(3C)(2-) oxide ions respectively.