Cubic Eu3+ centres in fluorite-type crystals

New Observations on the Pressure Dependence of Luminescence from Eu2+-Doped MF2 (M = Ca, Sr, Ba) Fluorides

“…The three sharp peaks at 2.17, 2.00, and 1.97 eV are from the 5 D 0 f 7 F 1 , 5 D 0 f 7 F 2 , and 5 D 0 f 7 F 4 transitions of Eu 3+ ions, respectively. 15,16 These sharp peaks remain almost constant at different pressures. At low pressures, the dip superimposed on the PL spectra is due to the absorption by a defect state of the front diamond in the DAC.…”

Hypersensitive Luminescence of Eu3+ in Dimethyl Sulfoxide As a New Probing for Water Measurement

“…The sharp and narrow bands in the excitation and emission spectra are corresponding to the f-f transitions of the Eu ion, and the emissions within the range of 575-725 nm are due to 5 D 0 f 7 F 1-4 transitions of Eu 3þ . 32,33 The two weak emission peaks at 536 and 555 nm originated from transitions of 5 D 1 f 7 F 1 and 5 D 1 f 7 F 2 of Eu 3þ . 34 The absorption peaks in the excitation spectrum are from the ground state of 7 F 0 to the high energy levels of Eu 3þ , and their assignments are labeled in the spectrum in Figure 2.…”

Laser spectroscopy of Eu3+ centers in CaF2:Eu–CdF2 superlattices

“…However, we believe this asymmetry alone is not sufficient to explain the shift of the excitation and emission wavelengths between the interface and remote centers. Jouart et al [10] list 5 D 1 level energies for the cubic centers in CaF 2 and CdF 2 as 19,030 and 19,023 cm −1 , respectively, i.e. there is a 7 cm −1 shift when all 12 cations around the Eu 3+ are changed from Ca 2+ to Cd 2+ .…”

“…In fact even at modest temperatures below 300 K, the interstitial F − ion of the A center can have sufficient mobility to move between adjacent interstitial sites [13]. Thus a bulk crystal prepared in the normal manner is expected to have charge-compensated centers dominating over any cubic centers until the concentration of Eu ions becomes very high [10].…”