Spin Polarization of Fluorine Nuclei in the Si/CaF<Subscript>2</Subscript> Nanostructure Under Optical Excitation

The laws of fluorine nuclear spin polarization in the Si/CaF₂ nanostructure under optical excitation of the charge carriers in it has been considered theoretically. It has been shown that maximum values (up to 3% of the concentration of nuclei in the lattice) are attained under a high rate of optical excitation (>10⁻⁹ sec⁻¹) when the nuclear spin diffusion process and the Auger recombination prevail. In this case, the nuclear relaxation time in an individual layer reaches 100–300 sec and the spin diffusion radius decreases to 0.3 nm. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 3, pp. 397–403, May–June, 2005.     

Bridging charge-orbital ordering and Fermi surface instabilities in half-doped single-layered manganite La(0.5)Sr(1.5)MnO₄

The single-layered half-doped manganite La(0.5)Sr(1.5)MnO? (LSMO), was studied by means of the angle-resolved photoemission spectroscopy (ARPES), scanning tunneling microscopy (STM), and resistivity measurements. STM revealed a smooth reconstruction-free surface; the density of states, extracted from photoemission and tunneling spectroscopy, is in agreement with transport measurements. The derived from ARPES Fermi surface (FS) nesting properties correspond to the known pattern of the charge-orbital ordering (COO), which implies that FS instability is related to the propensity to form a COO state in LSMO.     

Unique determination of multidimensional submanifolds of Euclidean space from the Grassman image

Translated from Matematicheskie Zametki, Vol. 51, No. 1, pp. 8–15, January, 1992.     

Kinetic properties of vanadium compounds intercalated into the matrix of lamellar zirconium phosphate

The intercalation of vanadium compounds into the matrix of lamellar zirconium phosphate leads to a significant increase in the activity and selectivity of vanadium oxide catalytic sites in the gas phase oxidation of benzene to malefic anhydride.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 32, No. 6, pp. 372–375, November-December, 1996.     

Model of deconfinement phase transition in lattice quantum chromodynamics

Institute of Theoretical Physics, Ukrainian SSR Academy of Sciences. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 80, No. 3, pp. 381–390, September, 1989.     

Vibrations of an axially polarized piezoceramic cylinder during electrical loading

Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Prikladnaya Mekhanika, Vol. 25, No. 11, pp. 15–19, November, 1989.     

An enormous vibrational motion: the gas-phase structure of dimethyl-bis(methoxyethynyl) germanium

The structure of dimethyl-bis(methoxyethynyl) germanium has been determined in the gas phase by electron diffraction utilising flexible restraints from quantum chemical calculations. Theoretical methods (B3LYP/6-311+G* and MP2/6-311+G*) predict a low barrier to rotation of the methoxy groups in the molecule in addition to low-frequency vibrations of the long ethynyl chains. In the equilibrium structure the Ge-C[triple bond]C angles of the two methoxyethynyl fragments in the molecule are computed to deviate by up to 4 degrees from the linear arrangement. As a consequence of low-frequency large-amplitude vibrational motion the experimental structure of these fragments without applying vibrational corrections deviates considerably from linearity, while the structure corrected for vibrational effects using the harmonic approximation and taking into account a non-linear transformation between internal and Cartesian coordinates (r(h1)) shows closer agreement with theory. The main experimental structural parameters of dimethyl-bis(methoxyethynyl) germanium (r(h1)) are: r(Ge-C)(mean), 192.5(1) pm; DeltaGeC =r(Ge-C(methyl))-r(Ge-C(ethynyl)), 4.5(5) pm, r(C[triple bond]C)(mean), 122.8(2) pm; r(C-O)(mean), 138.9(3) pm; DeltaCO =r(C(methyl)-O)-r(C(ethynyl)-O), 14.5(2) pm, r(C-H)(mean), 109.1(4) pm; [angle](X-C-H)(mean)(X = Ge,O), 109(1) degree; [angle]C(ethynyl)-Ge-C(ethynyl), 108.1(4) degree; [angle]C(methyl)-Ge-C(methyl), 113.4(5) degree; [angle]Ge-C[triple bond]C, 163(1) degree; [angle]C[triple bond]C-O, 176(2) degree; [angle]C-O-C, 115.2(6) degree; methoxy group torsion, tau, 36(9) degree from the position in which the C-O bond eclipses the further Ge-C(ethynyl) bond.     

Synthesis and Stereochemistry of 3-Hydroxy-1,2,3,6-tetrahydropyridines

A series of 1-benzyl-3-hydroxy-1,2,3,6-tetrahydropyridines, multipurpose synthons for fine organic synthesis and potential antiviral compounds, was prepared by the rearrangement of a number of 1-benzyl-3,4- epoxypiperidines under treatment with lithium amides. 3,4-Epoxypiperidines were obtained by oxidation of 1,2,5,6- tetrahydropyridines trifluoroacetates with a trifluoroperacetic acid. Convenient synthetic routes were found and developed. A conformation analysis of the series of stable 3,4-epoxypiperidines and 3-hydroxy-1,2,3,6- tetrahydropyridines was carried out.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 2, 2005, pp. 281–287.Original Russian Text Copyright © 2005 by Grishina, Borisenko, Veselov, Petrenko.     

Gas-phase electron diffraction studies of the icosahedral carbaboranes, ortho-, meta- and para-C2B10H12

The molecular structures of the three closo-carbaboranes, ortho-, meta- and para-C2B10H12, were experimentally determined using gas-phase electron diffraction (GED). All unique bond distances for ortho and meta carbaboranes were determined experimentally for the first time. For ortho-carbaborane (RG= 0.046), a model with C2v symmetry refined to give bond distances of 1.624(8) A for C-C, 1.093(8)A for C-H and 1.192(3)-1.196(3) A for B-H. For meta-carbaborane (RG= 0.040) a model with C2v symmetry refined to give a CC distance of 2.575(9) A. For para-carbaborane (RG= 0.062) a model with D5d symmetry refined to give a C-B bond distance of 1.698(3) A, B2-B3 of 1.785(1), B2-B7 of 1.774(4) and CC of 3.029(5)A. These GED structures are compared with geometries from other experimental diffraction methods (neutron, X-ray) and ab initio calculations.