Resonant phonon scattering by radiation-induced crystal defects inCaF2

Defect luminescence in CaF2 nanoparticles

“…1 and 2) due to luminescence reabsorption by F-centers. It is known that the absorption peak of F-centers in СаF 2 crystals at 80 K coincides with the 390 nm wavelength and shifts to 375 nm at room temperature [38]. Thus, the peaks at 352 and 410 nm (Fig.…”

“…It was also established earlier that the source of radiation defects in CaF 2 single crystals is non-radiative decay of STE that can cause the formation of both F-H-, and α-І-centers [11,38,39].…”

Investigation of Precipitation in Czochralski Silicon by Phonon Spectroscopy

“…It has the virtue of high sensitivity for interstitial oxygen in silicon by resonant scattering from the low-energy transition at 878 GHz (3.63 meV) [15] and it offers the possibility to observe geometrical acoustic resonances by extended defects because of the small acoustic wavelengths of some tens of nm involved. This possibility was demonstrated by Wurster et al [16] for Ca clusters in irradiated CaF 2 . In that case not only the size distribution but also the contribution of inelastic scattering could be analyzed.…”

Defects in U3+:CaF2 single crystals grown under different conditions by the temperature gradient technique

“…In this range, the increase of absorption coefficient for U-1 is larger than that for U-2. The absorption coefficient in the range 260-370 nm decreased, where the band peaking at 276 nm is due to H centers [18] (an F 2 -molecular ion situated at a single F -site). According to AA values in spectra a and b, more U 4+ ions are induced by thermal activation in U-1 than in U-2.…”