E. I. Zinin

Time-resolved luminescence of CeF3 crystals excited by X-ray synchrotron radiation

Abstract Under X-ray synchrotron radiation (SR) of storage ring VEPP-3 excitation time-resolved luminescence spectra and decay curves for two different CeF 3 crystals have been measured. The temperature dependence of the decay kinetics of emission at 300 nm of new pure CeF 3 crystal has been studied. The maximum of the intensity of this emission was observed at 390 K under SR X-ray excitation. The results are compared with data obtained under UV SR excitation and are discussed in terms of two models of luminescence quenching.

Time‐resolved XEOL spectroscopy of new scintillators based on CsI

Spectral and kinetic properties of the fast intrinsic ultraviolet luminescence of CsI single crystals either pure or doped by Br, Cl, Rb, or K, studied under different types of excitation at temperatures from 80 to 550 K, are presented. Since conventional models of intrinsic luminescence in their ‘‘pure’’ form fail to explain the observed properties of the UVL, a new one should be worked out taking into account collective interaction of neighboring excitations and defects, created by ionizing particles, which form clusters of excitations. It has been shown that luminescence decay time can be controlled by doping with homologs.

Research of energy transfer in Y2SiO5Ce, Tb single crystals by time resolved luminescence spectroscopy

Abstract The energy transfer between the rare-earth ions in Y s SiO 5 Ce, Tb crystals has been investigated with the use of the methods of luminescence spectroscopy with subnanosecond time resolution and excitation by pulsed synchrotron radiation (SR). Effective nonradiative energy transfer between Ce 3+ and Tb 3+ -ions which is realized by the inductive resonance mechanism has been observed. The absolute constant of the energy transfer speed K t and the probability of transfer have been determined. A dependence of the energy transfer parameters on the SR-excitation density has been discovered and investigated. Increasing of the density of the SR-excitation by a factor of 10 results in the increase of K t from 4.8 × 10 8 up to 1.7 × 10 10 mol −1 s −1 .

Optical spectroscopy of free and bound excitons in lithium hydride crystals excited with synchrotron radiation

Abstract Measurements of the luminescence spectra and decay times of the free and bound excitons in pure LiH and compounded LiHLiF crystals at T = 78 K were performed at the optical spectroscopy station with time resolution in the SR channel on the VEPP-3 storage ring.

Vacuum ultraviolet and X-ray emission spectroscopy of anion and cation excitons in oxide crystals

The results of a combined experimental investigation into the radiative relaxation of anion and cation excitons during selective vacuum ultraviolet-(up edge) and soft X-ray (core) excitation of berylliumcontaining BeO, Be2SiO4 and La2Be2O5 crystals are presented. They indicate that the relaxation of anion and cation excitons in multi-component oxides occurs in the same local fragments of the crystal lattice, due to their higher predisposition (in comparison with other fragments) to short-lived distortions. It has been found that in La2Be2O5 crystals characterized by a considerable difference in the ionic radii of cations (beryllium and lanthanum), the beryllium-oxygen tetrahedra do not participate in exciton relaxation processes.

Time-resolved spectroscopy of natural and synthetic BeO crystals

The results of comparative luminescence investigation of natural and synthetic BeO crystals are presented. Time-resolved luminescence (2.5–8 eV) and luminescence excitation spectra, and the kinetics of glow decay were measured using ultraviolet-vacuum-ultraviolet (VUV) synchrotron radiation (5–22 eV) or x-radiation (50–620 eV or 3–62 keV) ranges. X-ray and thermostimulated luminescence of natural BeO crystals were compared to the glow of additively colored synthetic crystals. The characteristic luminescence of F and F+ centers was found in natural crystals. In synthetic crystals similar luminescence is observed only after additive or radiation coloration by virtue of the creation of F− and F+ centers on anion vacancies. The defects found in the crystal lattice of a natural BeO crystal testify to the degree of mineral metamictization of the given deposit.

Fast intrinsic luminescence of RbI and KI crystals excited by X-ray synchrotron radiation

Abstract Luminescence spectra and decay kinetics of the fast intrinsic luminescence of RbI and KI crystals at temperatures of 80 and 300 K have been measured with pulsed X-ray synchrotron radiation (SR) excitation. At 80 K the emission spectra show the well-known fast emission bands centered at 3.84 eV in RbI and at 4.15 eV in KI. At room temperature subnanosecond (∼ 100 ps) emission bands with non-exponential decay kinetics are observed at 3.7 eV in RbI and at 4.0 eV in KI. These two bands may be associated with high temperature fast intrinsic luminescence of CsI.

Photoluminescence and X-ray fluorescence of complex oxides upon selective photon excitation

The visible and ultraviolet photoluminescence of multicomponent beryllium-containing oxides Be2SiO4, BeAl2O4, and Be3Al2Si6O18 upon selective photon excitation in the vacuum ultraviolet (6–15 eV) and ultrasoft X-ray (50–150 eV) ranges is investigated. X-ray fluorescence in the range 60–115 eV upon excitation with X-ray photons is independently studied. Using comparative analysis of dissipation of the primary electronic-excitation energy via two channels of radiative relaxation of secondary excitations, the role of different cation sublattices of multicomponent oxides in the fundamental processes of electronic-excitation evolution is established.

Spectroscopic investigations of wide-band fluoride crystals doped with ions of some rare-earth elements under X-ray excitation

Results of studying the properties of luminescence spectra of wide-band fluoride CaF2, Ca0.9Y0.1F2.1, Na0.4Y0.6F2.2, Na0.4Yb0.6F2.2, and BaYb2F8 crystals (pure and doped with Ce3+ and Yb3+ ions) under synchrotron radiation excitation with energies ranging from 3 to 60 keV are presented. Luminescence spectra are obtained in the region 200–600 nm. Transmission spectra are studied, and the effect of intense short-wavelength radiation on the optical properties of these crystals is studied.

Orientational effects in luminescence of wide-gap crystals under polarized synchrotron radiation

Abstract Use of synchrotron radiation of X-ray range are received premeditated population of certain states of optical centers in beryllium oxide (Eg = 10.63 eV), and also display of orientational effects in other wide-band dielectrics and semiconductors with lowered local symmetry of a crystal lattice (α-Al2O3, LiB3O5, ZnO). The assumptions about the nature of this phenomena are presented.