Electrolytic coloration and spectral properties of OH−- and Cu+-codoped NaCl crystals

OH−- and Cu+-codoped NaCl crystals are colored electrolytically by using a pointed anode and a flat cathode at various temperatures and under various voltages. Absorption and fluorescence spectral properties of colored crystals are investigated. Absorption, excitation and fluorescence spectra reveal existence of V2, V2m, V3, OH−, U, UA, O2−–Va+, O2+, Cu+, Cu0, Cu− and OH−-perturbed Cu+ color centers in colored crystals. Formations of color centers are explained.