(Pb,Gd)3(Al,Ga)5O12:Ce3+,Eu3+ films have been grown by liquid-phase epitaxy from a supercooled high-temperature solution based on the PbO–B2O3 system. We have measured and analyzed their absorption, photoluminescence, and photoluminescence excitation spectra. The results demonstrate that there is energy transfer from Ce3+ to Eu3+, resulting in Ce3+ luminescence quenching.

Ce-doped (Pb, Gd) 3 (Al, Ga) 5 O 12 and Ce-doped (Bi, Gd)3(Al, Ga) 5 O 12 single crystalline garnet films were grown using liquid-phase epitaxy method from supercooled PbO–B 2 O 3 - and Bi 2 O 3 –B 2 O 3 -based melt solutions on substrates from Gd 3 Ga 5 O 12 , Gd 3 (Al, Ga) 5 O 12 and Y 3 Ga 5 O 12 single crystals. Optical absorption, photo- and cathodoluminescent and scintillation properties of the films were studied. Ce-doped (Pb,Gd) 3 (Al, Ga) 5 O 12 and Ce-doped (Bi, Gd) 3 (Al, Ga) 5 O 12 garnet films can be used as a fast phosphor and scintillation screens.

Using the experimental setup for poling film samples with capability of continuous monitoring of generation signal of second harmonic, the conditions of effective orientation of chromophore molecules based on polyfluoro-substituted triaryl pyrazoline and dicyan-substituted isophoron in micron films of polycarbonate are determined. The second harmonic is excited with the pulse Nd:YAG laser with 1064 nm when chromophore molecules are oriented in the field of corona discharge. The dependences of signal level of the second harmonic on the potential at field mesh and on the potential at needle electrode are measured.

Ce-doped (Pb, Gd)3(Al, Ga)5O12 single crystalline garnet films were grown using liquid-phase epitaxy method from supercooled PbO–B2O3-based melt solutions on substrates from Gd3Ga5O12 and Gd3Al2.26Ga2.74O12 single crystals. Optical absorption and photo- and cathodoluminescent properties of these epitaxial garnet films were studied. Ce-doped (Pb, Gd)3(Al, Ga)5O12 garnet films can be used as a fast phosphor in the design of a PIF-01 electron-optical converter.

The optical absorption and photoluminescence properties of cerium-activated (Pb,Gd)3(Al,Ga)5O12 epitaxial films are studied. The films are grown on single-crystal (111)-oriented Gd3Ga5O12 substrates by liquid-phase epitaxy from supercooled PbO – B2O3 melt solutions at different concentrations of gadolinium, cerium, and aluminium oxides in the charge. The photoluminescence band of Ce3+ ions is shown to peak at 532 nm. The highest cathodoluminescence yield of about 51500 photons MeV−1 at a decay time of the slow component of 61.0 ns (light yield fraction 68%) is found for the Pb0.01Ce0.03Gd2.96Al3.14Ga1.86O12 film, grown from melt solution with gadolinium oxide, cerium oxide, and aluminium oxide concentrations of 0.4, 0.2, and 4.5 mol % in the charge, respectively. Epitaxial films with these spectroscopic characteristics are promising for application in scintillation screens.

Изучено влияние ионов Al и Се на оптическое поглощение и люминесценцию монокристаллических пленок (Pb,Gd)3 - уСеуAlхGa5 - хO12, где х = 2.02, 2.09, 2.13, 2.17, 2.22 и у = 0.02, 0.06, 0.07, выращенных методом жидкофазной эпитаксии из переохлажденных растворов-расплавов на основе системы PbO B2O3 на монокристаллических подложках Gd3Ga5O12 с ориентацией (111) при концентрациях оксида алюминия 2.0, 2.1 и 2.2 мол. % и оксида церия 0.03 и 0.2 мол. % в шихте. Определен сдвиг полос поглощения уровней 5d1 и 5d2 ионов Ce3+ в зависимости от концентрации Al в пленках. Показано, что интенсивность полос люминесценции иона Се3+ увеличивается с ростом содержания Al и Се в пленках.

We have studied the effect of Al and Ce ions on the optical absorption and luminescence of singlecrystal (Pb,Gd)3–y Ce y Al x Ga5–x O12 (x = 2.02, 2.09, 2.13, 2.17, 2.22; y = 0.02, 0.06, 0.07) films grown on (111)-oriented single-crystal Gd3Ga5O12 substrates by liquid-phase epitaxy from supercooled high-temperature solutions using solvents of the PbO–B2O3 system and growth charges containing 2.0, 2.1, or 2.2 mol % aluminum oxide and 0.03 or 0.2 mol % cerium oxide. The shift of the absorption bands of the Ce3+ 5d 1 and 5d 2 levels has been determined as a function of Al concentration in the films. The intensity of the Ce3+ luminescence bands of the films has been shown to increase with increasing Al and Ce concentrations.

Epitaxial films of Ce-doped Gd-3(AlxGa1-x)(5)O-12 with x = 0.00, 0.22, 0.31, 0.38 formula units were grown using liquid-phase epitaxy method, and their optical properties were studied. The emission of Ce3+ ions can be observed only when Al3+ ions are incorporated into the garnet structure, resulting in a shift of the 5d Ce3+ states from the conduction band to the bandgap. It is shown that the shift is caused by the cumulative effect of gradual low-energy shift of the lowest 5d level of Ce3+ and the raise of the garnet bandgap energy with increasing Al3+ concentration. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.

2,2′-Diaryl-5,5,5′,5′-tetramethyl-3,3′-bi(pyrrol-3-ylidene)-4,4′(5H,5′H)-dione 1,1′-dioxides containing a carboxy, alkoxycarbonyl, or carbamoyl group in the para position of one or both benzene rings were synthesized. These compounds may be regarded as cyclic dinitrones with conjugated C=C bond. Mild aminolysis of carboxy groups in the title compounds may be used to introduce dinitrone fragments into oligonucleotide or polypeptide structures. Electrochemical reduction of the resulting amides involves reversible oneelectron transfer in the first step at a near-zero potential, which makes it possible to use the title compounds as electrochemically active labels in applied bioorganic electrochemistry.

Radical anions of cyclic dinitrones, 3,3′-bi(2-R-5,5-dimethyl-4-oxopyrrolinylidene) 1,1′-dioxides (R = Me, Ph, But, CF3) have been studied by ESR in combination with quantum chemical calculations of geometrical parameters and isotropic hyperfine interaction constants by the DFT/PBE methods in the 3z basis set and UB3LYP in the 6–31+G* basis set with allowance for the solvation in the framework of continual PCM model. The radical anions were generated electrochemically by reduction of their neutral precursors in MeCN-H2O solvent mixtures and found to possess enough stability for measurement of their ESR spectra in a wide range of the mixture compositions. Radical anions of compounds of nitrone series were generated and characterized in MeCN-H2O mixtures and water (for the dinitrone with R = Me) for the first time. Differences in the solvent depending behavior of the nitrogen hyperfine interaction constants in the series of radical anions with various substituents R are explained by competition of transsolvation and structural effects.

Single-crystal gadolinium gallium garnet films have been grown by liquid-phase epitaxy on (111) Gd3Ga5O12 substrates from supercooled Bi2O3-B2O3 fluxed melts at different Gd2O3 concentrations. The luminescence spectra of the films have been measured at 10 and 300 K under unmonochromatized synchrotron X-ray excitation and selective UV synchrotron excitation. The Bi3+ luminescence is discussed.

The stray magnetic fields of rock samples with inclusions of the magnetic grains and magnetic crystals were observed using epitaxial (Bi,Lu)3(Fe,Ga)5O12 films with uniaxial magnetic anisotropy. Basalt rocks with inclusions of titano-magnetite and native elsen but also crystals of titano-magnetite and pyrrhotin were investigated. Stray magnetic fields were visualized with the Faraday Effect.

We have studied the effect of Pb2+ impurities and Pb2+-Pb4+ pairs on the optical absorption between 200 and 860 nm in single-crystal gadolinium gallium garnet films grown by liquid-phase epitaxy from supercooled PbO-B2O3 fluxed melts containing 0.1–0.5 mol% gadolinia.

Single-crystal films of complex composition (Bi, Gd)(3) (Ga, Pt)(2) Ga-3 O-12 on Gd-3 Ga-5 O-12 (111) substrates are synthesized by liquid- phase epitaxy from a supercooled solution - melt based on Bi2O3 - B2O3 flux. Optical absorption of Bi3+ and Pt3+ ions in these films is investigated in the wavelength range from 200 to 860 nm.

Single-crystal films of complex composition (Bi,Gd)3(Ga,Pt)2Ga3O12 on Gd3Ga5O12(111) substrates are synthesized by liquid-phase epitaxy from a supercooled solution-melt based on Bi2O3-B2O3 flux. Optical absorption of Bi3+ and Pt3+ ions in these films is investigated in the wavelength range from 200 to 860 nm.

Gadolinium gallium garnet single-crystal films containing terbium are grown through liquid-phase epitaxy from a supercooled solution melt in the PbO-B 2 O 3 system. The optical absorption spectra in the wavelength range 0.2–10.0 μm and the luminescence spectra excited by synchrotron radiation with energies in the range 3.5–30.0 eV are investigated at temperatures of 10 and 300 K. It is revealed that the optical absorption spectra contain an absorption band with the maximum at a wavelength λ ≈0.260 μm, which corresponds to the spin-allowed electric dipole transition between the electronic configurations 4 f 8 ( 7 F 6 ) → 4 f 7 ( 8 S )5 d of the Tb 3+ ions. The narrow low-intensity absorption bands attributed to the 4 f → 4 f transitions from the 7 F 6 ground level to the 7 F 0–5 multiplet levels of the Tb 3+ ions are observed in the wavelength range 1.7–10.0 μm. In the luminescence spectra measured at a temperature of 10 K, the highest intensity is observed for a band with the maximum at a wavelength λ ≈ 0.544 μm, which is associated with the 5 D 4 → 7 F 5 radiative transition in the Tb 3+ ion.

The phosphorescence of a Gd 3 Ga 5 O 12 single crystal grown by the Czochralski method is discussed. The phosphorescence was excited by UV radiation of a deuterium lamp.