Optical, infrared and EPR spectroscopy of CaF2:Ce3+ crystals co-doped with Li+ or Na+

Large anomalies due to insufficiency of Madelung embedding inab initiocalculations of4f−5dand4f−6sexcitations

“…23 The charged defects created by this type of doping in fluorites can be locally compensated with interstitial fluoride ions 24 or nonlocally compensated with distant codoping ions like Na + . 25 Although the effect of local compensations on the absorption and emission spectra is an interesting issue that will be the subject of further ab initio studies, the purpose of this paper is to claim the importance of a correct embedding and, here, we will only study the nonlocally compensated defect. It is an O h cubic defect where the Ce 3+ impurity is surrounded by a first coordination shell of eight F − anions.…”

Electron paramagnetic resonance enhanced crystal field analysis for low point-group symmetry systems: C2vsites in Sm3+:CaF2/SrF2

“…Various configurations for these centres are given by Pack et al [21] who studied the 4f 1 → 4f 0 5d 1 transitions of Na + codoped Ce 3+ :CaF 2 and Ce 3+ :SrF 2 crystals. While their work suggested the presence of multiple Na + charge compensated centres, a later study focusing on EPR intra-and inter-configurational transitions, of Ce 3+ :CaF 2 optimally codoped with either Li + or Na + , suggests the presence of three main centres [22]. A remotely charge compensated cubic (O h ) centre, an orthorhombic C 2v symmetry centre associated with a nearest neighbour [1 1 0] alkali ion, and a modified tetragonal centre having an on-axis [2 0 0] alkali ion in the next nearest neighbour position.…”

Photoluminescence studies of γ-irradiated CaF2:Dy:Pb:Na single crystals

“…The Na-and Ce-doped CaF 2 single crystals were studied for their optical, IR and EPR spectroscopic characteristics [1]. The crystal was tried as a UV laser active medium in the near-UV region.…”