Luminescence spectra of Pr3+ in 15 titanate and vanadate lattices have been measured under LW excitation. They are characterized by a dominant red luminescence assigned to transitions from the D-1(2) level to the ground state. The quenching of the otherwise prominent blue luminescence from P-3(0) state is ascribed to a relaxation pathway involving a low-lying Pr3+-Mn+ (Mn+ = Ti4+ or V5+) intervalence charge transfer (IVCT) state. Complete quenching of the P-3(0) emission takes place when the IVCT bands are located in the 2650028 000 cm(-1) range and the shortest Pr3+-Mn+ distances are in the 3.15-3.30 angstrom range. (c) 2005 Elsevier B.V. All rights reserved.