Vacuum ultraviolet synchrotron measurements of excitons in $NaMgF_3:Yb^{2+}$

Results of a vacuum ultraviolet spectroscopic characterization of NaMgF$_{3}$:Yb$^{2+}$ are presented. The material demonstrates emission features associated with self-trapped excitons and impurity-trapped excitons. The emission features noticeably overlap giving rise to a broad emission band from 17 000 to 35 000 cm$^{−1}$ at a sample temperature of 8 K. To identify the true profiles of the emission features we have used a deconvolution procedure. The deconvolution was possible due to the thermal quenching of self-trapped excitons at room temperature that allowed for direct observations of the impurity trapped exciton emission band. Energy transfer between host electronic excitations (excitons and e–h pairs) and Yb$^{2+}$ ions leading to the formation of impurity-trapped excitons is evident from excitation spectra