Energy and phase relaxation of phosphorescent F centers in CaO

Abstract

In this paper we study the temperature-induced homogeneous broadening of the no-phonon line in the emission spectrum of the F center in CaO. The linewidth can be fitted to n̄(n̄+1), where n̄ is the thermally averaged occupation number of phonons with a frequency of 90 cm−1. The results are characteristic of elastic scattering of pseudolocalized phonons at the defect site. These phonons also appear to dynamically couple the Jahn–Teller components of the F center in the photoexcited 3T1u state and thus give rise to a temperature dependence of the lifetime of this phosphorescent state. Finally, from experiments using laser-selective excitation it is concluded that the zero-phonon emission peaking at 571.1 nm does not originate in the F center.