Photoluminescence decay studies of emitting species on MgO nanocubes at room temperature provide evidence of three sur- face species characterized by an excitation and emission wave- length couple {l exc ;l em }.Species A corresponds to {l exc =240 nm; l em =380 nm},whereas the couple {l exc =280 nm;l em =470 nm} 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 in- trinsic emission and energy transfer processes.Lifetime values in- dicate that phosphorescence is taking place,and species A,B and B ' are identified as edge O 2 4C ,corner O 2 3C and kink O 2 3C oxide ions respectively.