Electrolytic coloration and spectral properties of natural fluorite crystals containing oxygen impurities

摘要

Natural fluorite crystals containing oxygen impurities are colored electrolytically by using a pointed cathode and a flat anode at various temperatures and voltages. F and F_2 color centers are produced in colored fluorite crystals. O~(2-)-V_a~+, O ~(2-)-V_a~+ aggregate, Yb~(2+), Ce ~(3+) and Sm~(2+) absorption bands are observed in absorption spectra of uncolored fluorite crystals. O~(2-)-V_a~+, O~(2-)-V_a~+ aggregate, Yb ~(2+), Ce~(3+), Sm~(2+), F, M (F_2) absorption bands and group of four absorption bands are observed simultaneously in absorption spectra of colored fluorite crystals. Current-time curve for electrolytic coloration of natural fluorite crystal and its relationship with electrolytic coloration process are given. Production and conversion of color centers are explained.