We present the results of ab initio calculations of several intrinsic and oxygen-containing defects in CaF including an center, a substitutional O ion, an O-vacancy dipole, and (O) and (O) centers. The calculations have been performed using a hybrid density functional and an embedded cluster method. The calculated optical absorption (OA) spectra and magnetic properties are in a very good agreement with available experimental data. It is suggested that isolated substitutional O ions induce an OA band in the vacuum ultraviolet region at about 7 eV. The nature of the OA bands associated with O-vacancy dipoles and other, more complex, defects is clarified and corresponding luminescence mechanisms are discussed.
- Received 6 February 2011
©2011 American Physical Society