Study of electronic structures and absorption bands of BaMgF₄ crystal with F colour centre

The electronic structures of BaMgF₄ crystals containing an F colour centre are studied within the framework of the fully relativistic self-consistent Direc–Slater theory, using a numerically discrete variational (DV-X\alpha) method. It is concluded from the calculated results that the energy levels of the F colour centre are located in the forbidden band. The optical transition energy from the ground state to the excited state for the F colour centre is about 5.12 eV, which corresponds to the 242-nm absorption band. These calculated results can explain the origin of the absorption bands.