Computer Simulation of the Electronic Structures and Absorption Spectra for a KMgF3 Crystal Containing a Potassium Vacancy

CASTEP code,based on the density functional theory(DFT)Electronic structures and absorption spectra for a perfect KMgF_(3)crystal and a KMgF_(3)crystal containing a potassium vacancy V_(K)^(-)are optimized using the CASTEP density functional theory code.The calculated results indicate that the perfect KMgF_(3)crystal has no absorption in the visible energy region,however,a KMgF_(3)crystal containing V_(K)^(-)has an additional absorption band peaking at 565 nm,fitting well with the experimental result that KMgF_(3)irradiated by an electron has an additional absorption peak at 565 nm.It is reasonably predicted that the 565 nm absorption band is related to the existence of V_(K)^(-)in the KMgF_(3)crystal created by the electron irradiation.