Luminescence of Bi, Ag and Cu in natural and synthetic barite BaSO₄

The time-resolved laser-induced luminescence of natural barite BaSO₄ is compared with synthetically prepared BaSO₄-Bi, BaSO₄-Ag and BaSO₄-Cu. It is deduced that in natural barite the narrow orange band with λ_max = 625 nm, Δ = 40 nm and τ = 5 μs is connected with Bi²⁺ center. The narrow violet band with λ_max = 625 nm, Δ = 35 nm and τ = 1.7 ms is connected with Bi³⁺ center. The broad red band with λ_max = 635 nm, Δ = 140 nm and τ = 270 μs is connected with Ag⁺ center. The broad red band with λ_max = 750 nm, Δ = 110 nm and τ = 350 μs is connected with Cu⁺ center. Such luminescence centers are firstly considered in minerals.