Ab initio study of F-centers in alkali halides

J. HOYA; J.I. LABORDE; D. RICHARD; M. RENTERÍA

La Plata

Conferencia; HK 2010; 2011

Alexander von Humboldt Stiftung, UNLP

The structural and electronic properties of an electron trapped at vacant anion sites in alkali halides (F-center) have been investigated using ab initio electronic band structure calculations with the super-cell method. We used the Full-Potential Augmented-Plane Waves plus local orbital (FP-APW+lo) method in the framework of the Density Functional Theory (DFT), with a vacancy dilution of 1:64 in order to determine the spatial electronic charge density and band structure of the studied compounds. The defect introduces a donor level which has s-character. According to the dipole selection rule, the allowed F-center optical transition was also determined. Despite of the well-known underestimation in the transition energies we could obtain a qualitative agreement with the known experimental UV/Vis absorption energies.