Comparative quantum chemistry study of the F-center in lanthanum trifluoride

In this study we report the results of first principle quantum chemical modeling of electronic structure and spatial configuration of LaF₃ crystal containing the F-center. Theoretical predictions of atomic and electronic properties of LaF₃ are given by means of density functional theory. From our modeling we predict that the F-center placed at fluorine ion position between the lanthanum planes at tysonite LaF₃ is the most energetically stable. In order to interpret the structure of the optical absorption spectrum of X-irradiated LaF₃ we performed calculations of excited and transition states of the F-center within the embedded cluster formalism using time dependent density functional theory. Predicted transition energies and oscillator strengths of LaF₃ containing the F-center are in line with those recently measured.