Theoretical modeling of thermally activated luminescence quenching through charge transfer states in lanthanide complexes

A theoretical approach for the luminescence thermal quenching through ligand-to-metal charge transfer (LMCT) states in lanthanide compounds is developed. Considering single configurational coordinate models for both LMCT and intra-ligand states, expressions for the spectral overlap integrals involving a donor state, 4f-state (case 1) or an intra-ligand state (case 2), and the LMCT, were obtained. Comparison between theoretical and experimental results of quantum efficiencies for some coordination compounds is quite satisfactory.