[en] The absorption, excitation, photostimulation spectra and thermoluminescence creation spectra of pure BaFX (X=Br, Cl) and BaFX:Eu²⁺ single crystals were studied in the vacuum ultraviolet region 5-10 eV at temperatures 6-300 K. The creation of a V_k-related thermoluminescence peak was observed when the BaFX : Eu²⁺ crystal was illuminated with vacuum ultraviolet (VUV) photons with energy above 6 eV. Band-to-band transitions begin above 8-9 eV. Low temperature photostimulation spectra for Eu²⁺ luminescence created by 6-7 eV photons showed new bands in the infrared region, the intensities of which were directly proportional to the Eu²⁺ concentration. However, the same infrared photostimulation bands for exciton luminescence were observed also in undoped crystals after X-ray irradiation. The results show that trapped electrons and self-trapped holes were created by VUV photons in BaFX:Eu²⁺ crystals. It was concluded that Eu²⁺ ions assist in creation of free electrons and holes by photons with energy 2-3 eV lower than those of band-to-band transitions

No abstract available

[en] Two main methods of separation using the distillation method are given and evaluated, namely evaporation and distillation in carrier gas flow. Two basic apparatus are described for illustrating the methods used. The use of the distillation method in radiochemistry is documented by a number of examples of the separation of elements in elemental state, volatile halogenides and oxides. Tables give a survey of distillation methods used for the separation of the individual elements and give conditions under which this separation takes place. The suitability of the use of distillation methods in radiochemistry is discussed with regard to other separation methods. (L.K.)

[en] 1.3-dimethyl-2-imidazolidinone (dimethylethyleneurea - DMEU), a relatively new non-aqueous solvent of high polarity, was used as ligand in the preparation of nine coordination compounds with some zinc group halides. The compounds were characterized by elemental analysis, IR TGA, DTA and DSC. The metal-oxggen bond enthalpies were estimated, as well another thermochemical parameters. (author)

[en] The local coordination structures around the doping Yb²⁺ ions in sodium and potassium halides were calculated by using the first-principles supercell model. Both the cases with and without the charge compensation vacancy in the local environment of the doping Yb²⁺ were calculated to study the effect of the doping on the local coordination structures of Yb²⁺. Using the calculated local structures, we obtained the crystal-field parameters for the Yb²⁺ ions doped in sodium and potassium halides by a method based on the combination of the quantum-chemical calculations and the effective Hamiltonian method. The calculated crystal-field parameters were analyzed and compared with the fitted results. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

[en] A noble phenylsulfonyl reagent 8 having α-oxo (cyanomethylene)triphenylphosphorane ylide subunit readily condensed with various alkyl halides under basic conditions to afford β-alkyl-α-oxo-β-phenylsulfonyl (cyanomethylene)triphenylphosphorane ylides 9 in excellent yields. These sulfonyl ylides 9 were then reductively desulfonylated with Na(Hg)/Na₂HPO₄ in the presence of methanol to provide α-keto (cyanomethylene)-triphenylphosphorane ylides 2' in good to excellent yields. Our new synthetic approach offers an expeditious access to various α-keto (cyanomethylene)triphenylphosphorane ylides from alkyl halides utilizing a new phenylsulfonyl reagent as the key reagent under mild reaction conditions in good overall yields

[en] A one-pot efficient procedure for the synthesis of 2,4,5-triaryl-1H-imidazole derivatives in good to excellent yields by reaction between hexamethyldisilazane and arylaldehydes, benzyl alcohols, benzyl halides in the presence of molecular iodine has been developed. The remarkable advantages of this method are the simple workup procedure, high yields of products, and the availability of reagents

[en] Although tin halide perovskite has shown excellent photoelectric performance, its efficiency of solar cell is low compared with that of lead halide. In order to enhance the efficiency of tin halide perovskite solar cell, a deep understanding of the role of the defects in the perovskite absorption layer and at the electron transport layer (ETL)/absorber or absorber/hole transport layer (HTL) interface is very necessary. In this work, the planar heterojunction-based CH₃NH₃SnI₃ perovskite solar cells were simulated with the SCAPS-1D program. Simulation results revealed a great dependence of device efficiency on defect density and interface quality of the perovskite absorber. The defect density at the front interface is critical for high efficiency, and the polarity of the interface charge has a different impact on the device efficiency. Strikingly, an efficiency over 29% was obtained under the moderate simulation conditions. (paper)

[en] To the best of our knowledge, however, the niobium analogue of this phase, NbPS₆ has not been discovered yet. As a result of efforts to find new phases in this family, we were able to prepare a new phase with disordered metals with the halide flux method. Here, we report the synthesis and structure of a new mixed-metal disulfide thiophosphate, Nb_0.44Ta_0.56PS₆. Crystallographic data for Nb_0.44Ta_0.56PS₆ are given in Table 1. Selected interatomic distances and angles are given in Tables 3. The title compound is isostructural with the previously reported TaPS₆ and its structure is closely related to those of the quaternary alkali metal thiophosphates such as K_0.38TaPS₆, A₂Nb₂P₂S₁₂ (A = K, Rb), K_0.18TaPS₆, K_0.28TaPS₆, and Rb_0.09TaPS₆. As shown in other group 5 transition metal thiophosphates, the structure of the title compound is made up of the bicapped trigonal biprismatic [M₂S₁₂] unit (M = Nb, Ta) and the tetrahedral [PS₄] group. This structural motif has already been encountered in other group 5 metal (V, Nb, Ta) thiophosphates such as RbNb₂PS₁₀. In the title structure, the metal(M) site is occupied by statistically disordered Nb (0.44(1)%) and Ta (0.56(1)%) atoms. The metal atom is surrounded by eight S atoms in a bicapped trigonal prismatic arrangement

[en] A convenient Rh-catalyzed C-H arylation of imidazo[1,2-a]pyridines with a variety of aryl halides or triflates has been reported. This process afforded a range of biaryl compounds in excellent yields and showed high activity and broad scope