Magneto-optical spectroscopy and optical detection of EPR spectra of Yb<Superscript>3+</Superscript> paramagnetic centers with cubic symmetry in single crystals <Emphasis Type="Italic">Me</Emphasis>F<Subscript>2</Subscript> (<Emphasis Type="Italic">Me</Emphasis> = Cd,Ca, Pb)

Cubic paramagnetic centers formed by Yb³⁺ impurity ions in fluorite-type crystals MeF₂ (Me = Cd, Ca, Pb) have been investigated using electron paramagnetic resonance, magnetic circular dichroism, magnetic circular polarization of luminescence, Zeeman splitting of optical absorption and luminescence lines, and optical detection of electron paramagnetic resonance. The g factors of the ²Γ₇ state in the excited multiplet ² F _5/2 of Yb³⁺ ions in Me F₂ crystals, the hyperfine interaction constant ¹⁷¹ A (¹⁷¹Yb) for the excited multiplet ² F _5/2 in the CaF₂ crystal, and the energies and symmetry properties of all energy levels of Yb³⁺ ions in MeF₂ crystals are determined. The crystal-field parameters for the crystals under investigation are calculated.     

Effect of electron tunneling on the crystallization of nanostructured metal sols

Regularities of the self-organization of bimodal ensembles of nanoparticles into crystalline structures in metal lyosols are studied by the Brownian dynamics method. Differences in the thicknesses of adsorption layers, van der Waals, elastic, and electrostatic interactions, and random and dissipative forces, as well as variations in interparticle electrostatic interactions due to electron tunneling are taken into account in the model. Pair potentials for polydisperse ensembles of particles are analyzed and the correlation between the pattern of potential curves and the type of forming structures is revealed. The possibility of the selective coagulation of particles with different sizes by virtue of dissimilar charging at the moment of their approach is demonstrated. The kinetics of this process is investigated. Specific features of the crystallization of bimodal sols are discussed using real gold organosols as examples.     

Magnetic Structures and Magnetic Phase Transitions in Rare-Earth <Emphasis Type="Italic">R</Emphasis>Mn<Subscript>2</Subscript>Si<Subscript>2</Subscript> Intermetallic Compounds (<Emphasis Type="Italic">R</Emphasis> = Sm,Tb)

The magnetic structures that form in La_1–xR_xMn₂Si₂ (R = Sm, Tb) layered compounds with various concentrations x have been determined by magnetic neutron diffraction and magnetic measurements, and the magnetic phase diagrams have been built. It is shown that the formation of the magnetic structures is dependent not only on exchange interactions, but also on the type of the magnetic anisotropy of a rare-earth atom. It is found that, in La_1–xTb_xMn₂Si₂ compounds with 0.2 < x < 0.5, the competition of the Tb–Mn and Mn–Mn interlayer exchange interactions and the existence of a strong uniaxial magnetic anisotropy in the Mn and Tb sublattices leads to the frustrated magnetic state and prevents the formation of the long-range magnetic order in the Tb sublattice.     

Formation of two-dimensional lattices of magnetic domains in a harmonic magnetic field

New configurations of two-dimensional lattices of magnetic domains with symmetry described by the P2 and Cmm2 space groups are revealed in studying the formation of domain structures in a harmonic magnetic field. Two-dimensional lattices belonging to five space groups of the orthorhombic and hexagonal systems are observed in a single iron garnet film. Changes in the lattice configurations and in the lattice elements occur upon the variation of only one parameter of the applied magnetic field, namely, its frequency.     

Test of bell’s inequality using the one-atom micromaser

We examine a local realist bound in the case of a one-atom micromaser. It is shown that such a bound is violated using a simplified treatment of the micromaser. We consider the effect of dissipation in a proposed experiment with the real micromaser. It is seen that the magnitude of violation of a Bell-type inequality depends significantly on the cavity parameters.     

Qualitative and Quantitative Treatment of Thin-Layer Chromatograms of Incompletely Separated Synthetic Food Colors

A procedure for the qualitative and quantitative determination of dyes after thin-layer chromatographic separation is developed using an example of five synthetic food colors: Brilliant Blue, Tartrazine, Sunset Yellow, Ponceau 4R, and Azorubine. The chromatogram is scanned and saved in Windows 95/98 raster image format and processed by the Adobe Photoshop 5.0 program package. The procedure is applicable even when the dyes are incompletely separated on the chromatogram.     

Radiation-chemical treatment of flue gases from thermal power stations for the removal of mercury vapor

The efficiency of radiation-chemical treatment of flue gases from thermal power stations for removing nitrogen and sulfur oxides was examined as applied to the removal of mercury vapor from the gases. A kinetic scheme of the process was developed. It involves the liquid-phase oxidation of Hg by O₃ molecules formed under the action of ionizing radiation on the gas macrocomponents followed by adsorption of the oxidation products at soot particles. It was found that almost complete removal of mercury vapor is attained at typical radiation doses and soot concentrations in the flue gases.     

Tomography of Optical Single-Qubit Quantum Memory

JETP Letters - The mechanism of condensation of electron–hole pairs in the phase space in a highly degenerate semiconductor involving resonant photons of the electromagnetic field is...