Photochromism, UV-Vis, Vibrational and Fluorescence Spectroscopy of Differently Colored Hackmanite.

Because of the rich fluorescent color and unique photochromic properties, hackmanite has attracted many mineralogists. In this paper, the basic gemmological characteristics and photochromic and fluorescence mechanisms of four different colors of hackmanite are further investigated through the study of their structural, compositional, and spectroscopic features. The results show the change in the color of hackmanite in photochromism is caused by the joint action of the F-center and the oxygen hole centers. The change in the UV-Vis spectra may be caused by the superposition of two peaks. Under 365 nm UV excitation, the peak of fluorescence spectra of 662 nm is related to the ²∏_g→²∏_u transition of S₂⁻, the blue emission at 441 nm is caused by the ³P_0.1→¹S₀ transition of s² ions (Pb²⁺, Tl⁺, Sn²⁺ Sb²⁺), and at 541 nm is caused by the Mn²⁺ center. The results are helpful in deepening the understanding of photochromism, fluorescence mechanism, and its structure, expanding the application of hackmanite. [ABSTRACT FROM AUTHOR]