2,239 research outputs found

    Ab initio prediction of magnetically dead layers in freestanding γ\gamma-Ce(111)

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    It is well known that the surface of nonmagnetic α\alpha-Ce is magnetically ordered, i.e., γ\gamma-like. One then might conjecture, in agreement with previous theoretical predictions, that the γ\gamma-Ce may also exhibit at its surfaces even more strongly enhanced γ\gamma-like magnetic ordering. Nonetheless, our result shows that the (111)-surfaces of magnetic γ\gamma-Ce are neither spin nor orbitally polarized, i.e., α\alpha-like. Therefore, we predict, in contrast to the nonmagnetic α\alpha-phase which tends to produce magnetically ordered γ\gamma-like thin layers at its free surfaces, the magnetic γ\gamma-phase has a tendency to form α\alpha-like dead layers. This study, which explains the suppressed (promoted) surface magnetic moments of γ\gamma-Ce (α\alpha-Ce), shows that how nanoscale can reverse physical properties by going from bulk to the surface in isostructural α\alpha- and γ\gamma-phases of cerium. We predict using our freestanding surface results that a typical unreactive and non-diffusive substrate can dramatically influence the magnetic surface of cerium thin films in contrast to most of the uncorrelated thin films and strongly correlated transition metals. Our result implies that magnetic surface moments of α\alpha-Ce(111) can be suddenly disappeared by increasing lattice mismatch at the interface of a typical unreactive and non-diffusive substrate with cerium overlayers.Comment: 6 pages, 3 figures, 1 tabl

    Attenuating Consumer Reactance to Threatening Messages: The Moderating Role of Construal Level

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    While many persuasive communications tend to be perceived as increasing consumer choice, others, such as public service announcements, more or less forcefully restrict that choice. This research examines the effects of threats to freedom on receptivity to message information, as a function of the level of construal at which the message is processed. The findings indicate that consumers are more open to high threat message information at high (vs. low) levels of construal, and this pattern holds when construal level is manipulated via message wording (study one) or is non-consciously primed prior to message exposure (study two). Also, the results point to the level of detail at which the message is considered, and the resulting use of persuasion knowledge, as the underlying reason for this pattern of results (study three). Specifically, at high levels of detail (i.e. low construal) there is a greater use of persuasion knowledge and lower information receptivity in face of high threat to freedom messages. At low level of detail (high construal), by contrast, persuasion knowledge use is lower and receptivity to information in freedom threatening messages higher

    Electronic, dielectric and optical properties of two dimensional and bulk ice: a multi-scale simulation study

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    The intercalated water into nanopores exhibits anomalous properties such as ultralow dielectric constant.~Multi-scale modeling and simulations are used to investigate the dielectric properties of various crystalline two-dimensional ices and bulk ices. Although, the structural properties of two-dimensional (2D-) ices have been extensively studied, much less is known about their electronic and optical properties. First, by using density functional theory (DFT) and density functional perturbation theory (DFPT), we calculate the key electronic, optical and dielectric properties of 2D-ices. Performing DFPT calculations, both the ionic and electronic contributions of the dielectric constant are computed. The in-plane electronic dielectric constant is found to be larger than the out-of-plane dielectric constant for all the studied 2D-ices. The in-plane dielectric constant of the electronic response is found to be isotropic for all the studied ices. Secondly, we determined the dipolar dielectric constant of 2D-ices using molecular dynamics simulations (MDS) at finite temperature. The total out-of-plane dielectric constant is found to be larger than 2 for all the studied 2D-ices. Within the framework of the random-phase approximation (RPA), the absorption energy ranges for 2D-ices are found to be in the ultraviolet spectra. For the comparison purposes, we also elucidate the electronic, dielectric and optical properties of four crystalline ices (ice VIII, ice XI, ice Ic and ice Ih) and bulk water
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