Geometric and electronic structure of an N,N′-ethylene-bis(salicylaldiminato) zinc(II) molecule,ZnO<Subscript>2</Subscript>N<Subscript>2</Subscript>C<Subscript>16</Subscript>H<Subscript>14</Subscript>

Gas electron diffraction at a temperature T of 641(5) K is used to study the structure of an N,N′-ethylenebis(salicylaldiminato) zinc(II) molecule, ZnO₂N₂C₁₆H₁₄, further Zn(salen). The structure of a gaseous Zn(salen) complex has C ₂ symmetry and is characterized by a substantial turn of two chelating fragments of the ligand with respect to each other, and also by a big difference in the length of coordination bonds: r _h1(Zn-O)=1.902(7) Å r _h1(Zn-N)= 2.027(7) Å. Results of the DFT/B3LYP calculation with 6-31G* and CEP,TZV basis sets of the molecule structure well agree with the experimental data. The electronic structure of Ni(salen), Cu(salen), Zn(salen), and Zn(acacen) molecules is considered.     

Study of the electronic structure of Al(III) and Zn(II) complexes with organic ligands by quantum chemistry and photoelectron spectroscopy methods

Photoelectron spectra of aluminum complexes with 8-oxyquinoline (Alq ₃) and zinc complexes with N, N′-(o-phenylene)-bis(salicylidenediamine) (ZnSaloph) were measured on a photoelectron spectroscopy station at the Kurchatov Centre for Synchrotronic Radiation over the range of photon energies from 10 to 100 eV. Thin films of these compounds (∼20 nm thick) prepared by thermal evaporation onto glass substrates covered with transparent electroconductive layer of solid solution of tin and indium oxides (In₂O₃, SnO₂, ITO) were used as the objects of this study. The spectra of the valence band of these compounds and Al 2p level were measured. The data of quantum chemical calculations of the electronic structure obtained by the density functional theory are in good agreement with the experimental photoelectron spectra. Analysis of performance efficiency of the device was carried out on the basis of the results of calculation. This procedure does not result in decomposition of samples in the process of investigation and may be used for studying the electronic structure of coordination compounds with organic ligands in films.     

Unsteady motions of dense envelopes generated by ionization-shock fronts in the interstellar medium

The process of formation and acceleration of a neutral gas envelope during the propagation of an ionization-shock front in a spherical gas cloud is numerically modeled. The velocity and acceleration of the envelope as well as its mass variation with time are determined. The results obtained are compared with some approximate formulas known in the literature. The growth of small velocity perturbations in the dense gas and the effects of mass and momentum accumulation in “finger-like” condensations are studied in the framework of a two-dimensional model.     

Dynamics of Backscattering of Human Tissue on Exposure to a Low-Intensity Optical Radiation

The results of in vivo experiments on the spectral response of a human organism to the action of low–intensity optical radiation are presented. The dynamics of backscattering of diagnostic radiation in infrared and red spectral regions was recorded. The characteristic types of response to exposure have been revealed: a sudden increase or decrease in the value of the relative coefficient of backscattering accompanied by saturation.     

Untersuchung der Struktur und Eigenschaften der Polymeren des 2-Methyl-5-?thinylpyridins

Ohne Zusammenfassung     

Synthesis of 2-(1-alkoxyvinyl)pyridines

2-(1-Bromovinyl)pyridine, 2-ethynylpyridine, 2-(1-alkoxyvinyl)pyridines, and 2-(2-alkoxyvinyl)pyridines (the cis and trans isomers) were detected in the reaction mixture by mass spectrometry in the reaction of 2-vinylpyridine with bromine with subsequent dehydrobromination of the addition product with an alcohol solution of alkali. The conditions for the preparation of chromatographically pure compounds were found.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 647–650, May, 1978.     

Peculiarities of pluronic crystallization in thin films

The peculiarities of the crystallization of Pluronics from chloroform and aqueous polymer solution on mica surfaces are investigated with the atomic force microscopy method. It is shown that Pluronics in thin films form quasi two-dimensional crystalline structures of 10–12 nm thickness. Pluronic crystallization proceeds predominantly via the mechanism of diffusion-limited aggregation with the formation of dendrites. Three main morphological types of formed structures are identified including two types of dendrites (with 45° and 90° angles between branches) and elongated “needles.” It is shown that the film morphology depends on the polymer concentration, rate of solvent evaporation, and, probably, local gradients of concentration and temperature. Interaction with porphyrins establishes conditions for the local three-dimensional crystallization of Pluronics.     

A dynamic array of optical traps for deformation of elongated microobjects

A simple technique for the formation of an array of laser traps on the basis of phase diffraction gratings is proposed. The array allows trapping transparent elongated microobjects at several points simultaneously. The dynamic variation in the spatial disposition of the traps makes its possible to impose deformation on a trapped microobject. The technique proposed has been experimentally tested.     

Modeling of Molten Corium Oxidation in the Presence of an Oxide Crust on the Melt Surface

Technical Physics - In the case of a severe accident at a nuclear power plant with light-water reactors, the most effective method for localization of the formed melt (corium) is its retention in...