摘要：It has always been a mineralogical problem to accurately locate the occupancy of chromogenic ions in the structure of tourmaline. It is of great signifi-cance to indicate the target for color change of col-ored tourmaline and the in-depth development of its environmental protection properties.In this paper, the theory ofCASTEP quantum chemistry is used to study tourmaline lattice and its transition metal ion doping system.By studying its optical properties and density of states characteristics, the cause mecha-nism oftourmaline color is revealed. The calculation results show that the tourmaline crystal structure is doped with transition metal ion Mn2+ at Y site or Fe3+ doped with transition metal ion at Z site, the band gap width of the system is reduced, which helps tourmaline to respond to visible light and form color.The Y site is doped with Mn2+, which in turn facilitates the formation of a pink hue of tourma-line.The decrease of the band gap width is more ob-vious when the Y-site transition metal ion is doped than when the Z-site transition metal ion is doped.The doping of the Y site is the fundamental reason for the reduction of the band gap width.When the tourmaline crystal structure is doped, the band gap width decreases more obviously when the tran-sition metal ion is doped at the Y site than when the Z site is doped.The Z-site doping does not inde-pendently cause the band gap width to decrease. Con-strained by the Y-site,along with the obvious change of the atomic density of the Y-site, the Y-site doping has a stronger correlation with the reduction of the band gap width.The different positions of ions in the crystal structure of tourmaline have reference value for the in-depth development of tourmaline's envi-ronmental protection properties.
