Indium selenide: An insight into electronic band structure and surface excitations

We have investigated the electronic response of single crystals of indium selenide by means of angle-resolved photoemission spectroscopy, electron energy loss spectroscopy and density functional theory. The loss spectrum of indium selenide shows the direct free exciton at similar to 1.3 eV and several other peaks, which do not exhibit dispersion with the momentum. The joint analysis of the experimental band structure and the density of states indicates that spectral features in the loss function are strictly related to single-particle transitions. These excitations cannot be considered as fully coherent plasmons and they are damped even in the optical limit, i.e. for small momenta. The comparison of the calculated symmetry-projected density of states with electron energy loss spectra enables the assignment of the spectral features to transitions between specific electronic states. Furthermore, the effects of ambient gases on the band structure and on the loss function have been probed

Buy-out of pets because of their unproper treatment under civil legislation of Russia and post-soviet countries

The article deals with one of the compulsory methods of ownership right termination - the buy-out of pets if they are treated improperly. The authors draw attention to the specifics of this reason, which is associated with the buy-out subject, i.e. with an animal. They performed the comparative analysis of "pet improper treatment" and "cruel animal treatment" concepts, the problem of their differentiation is studie

High resolution characterisation of microstructural evolution in Rbx_{x}Fe2−y_{2-y}Se2_{2} crystals on annealing

The superconducting and magnetic properties of phase-separated A$_x$Fe$_{2-y}$Se$_2$ compounds are known to depend on post-growth heat treatments and cooling profiles. This paper focusses on the evolution of microstructure on annealing, and how this influences the superconducting properties of Rb$_x$Fe$_2-y$Se$_2$ crystals. We find that the minority phase in the as-grown crystal has increased unit cell anisotropy (c/a ratio), reduced Rb content and increased Fe content compared to the matrix. The microstructure is rather complex, with two-phase mesoscopic plate-shaped features aligned along {113} habit planes. The minority phase are strongly facetted on the {113} planes, which we have shown to be driven by minimising the volume strain energy introduced as a result of the phase transformation. Annealing at 488K results in coarsening of the mesoscopic plate-shaped features and the formation of a third distinct phase. The subtle differences in structure and chemistry of the minority phase(s) in the crystals are thought to be responsible for changes in the superconducting transition temperature. In addition, scanning photoemission microscopy has clearly shown that the electronic structure of the minority phase has a higher occupied density of states of the low binding energy Fe3d orbitals, characteristic of crystals that exhibit superconductivity. This demonstrates a clear correlation between the Fe-vacancy-free phase with high c/a ratio and the electronic structure characteristics of the superconducting phase.Comment: 6 figures v2 is exactly the same as v1. The typesetting errors in the abstract have been correcte

Legal-institutional typology of the subject of economic security

The article considers the problems of development of legal regulation in economic security. It evaluates the questions of formation of institutional factors, which define the system of legal prevention of threats to economic security. The study investigates the problems of transformation of economic security into one of the fundamental categories of the current right, which in turn defined the direction and depth of legal institutional structure of economic security at all levels. The factors impacting the growth of scientific and applied interest towards the conceptual, legal and institutional interpretations of economic security have been defined. Current legislation allowing to define the features of subject relations in the given sphere is being analysed. The research of acting Russian legislation, as well as the process of identifying the institutional and legal subjects of economic security, allow to construct the model of economic security with phenomenological method of thinking. Modern forms of institutionalization of legal support for economic security are based on the experience of leading regions across the world. The article points out that domestic legal science has significantly improved in conceptualizing the problems of economic security on the basis of classic examples of effective innovation activity. The article investigates the problems of legal institutionalization of the subjects of economic security, as well as carries out the search for effective measures to counteract the damaging tendencies in the economic sphere.peer-reviewe

Protein Dynamics Control of Electron Transfer in Photosynthetic Reaction Centers from Rps. Sulfoviridis

In the cycle of photosynthetic reaction centers, the initially oxidized special pair of bacteriochlorophyll molecules is subsequently reduced by an electron transferred over a chain of four hemes of the complex. Here, we examine the kinetics of electron transfer between the proximal heme c-559 of the chain and the oxidized special pair in the reaction center from Rps. sulfoviridis in the range of temperatures from 294 to 40 K. The experimental data were obtained for three redox states of the reaction center, in which one, two, or three nearest hemes of the chain are reduced prior to special pair oxidation. The experimental kinetic data are analyzed in terms of a Sumi–Marcus-type model developed in our previous paper,1 in which similar measurements were reported on the reaction centers from Rps. viridis. The model allows us to establish a connection between the observed nonexponential electron-transfer kinetics and the local structural relaxation dynamics of the reaction center protein on the microsecond time scale. The activation energy for relaxation dynamics of the protein medium has been found to be around 0.1 eV for all three redox states, which is in contrast to a value around 0.4–0.6 eV in Rps. viridis.1 The possible nature of the difference between the reaction centers from Rps. viridis and Rps. sulfoviridis, which are believed to be very similar, is discussed. The role of the protein glass transition at low temperatures and that of internal water molecules in the process are analyzed.España, Ministerio de Educación y Ciencia BFU2004-04914-C02-01/BMCJunta de Andalucía PAI CVI-26

Oxidation of methanol on Ru catalyst: Effect of the reagents partial pressures on the catalyst oxidation state and selectivity

In situ core level photoelectron spectroscopy and mass spectrometry have been utilized to study the methanol oxidation on a model RuO2 catalyst at pressures ranging from 10-6 to 10-1 mbar. The experiments were carried out varying the O2/CH3OH molecular mixing ratio from 0.25 to 3.3 and the reaction temperature from 350 to 720 K. The Ru 3d5/2 and O 1s core level spectra were used to characterise the dynamic changes in the Ru oxidation state by exposing the oxide pre-catalyst to different reagents partial pressures and temperatures. Full oxidation to CO2 + H2O or partial oxidation to CO + H2O + H2 have been observed in the whole pressure range for specific reaction conditions, which preserve the oxide catalyst state or reduce the oxide to metallic Ru. The selective oxidation to formaldehyde is observed only at pressures in the 10-1 mbar range, catalyzed by a RuO_x surface oxide formed by partial reduction of the oxide pre-catalyst

Strongly localized polaritons in an array of trapped two-level atoms interacting with a light field

We propose a new type of spatially periodic structure, i.e. polaritonic crystal (PolC), to observe a "slow"/"stopped" light phenomenon due to coupled atom-field states (polaritons) in a lattice. Under the tightbinding approximation, such a system realizes an array of weakly coupled trapped two-component atomic ensembles interacting with optical field in a tunnel-coupled one dimensional cavity array. We have shown that the phase transition to the superfluid Bardeen-Cooper-Schrieffer state, a so-called (BCS)-type state of low branch polaritons, occurs under the strong coupling condition. Such a transition results in the appearance of a macroscopic polarization of the atomic medium at non-zero frequency. The principal result is that the group velocity of polaritons depends essentially on the order parameter of the system, i.e. on the average photon number in the cavity array.Comment: 16 pages, 6 figure