Vanadium valency charge state in solid solutions ScNb2−2xTa2xVO9

Phase equilibria in the Sc₂O₃-V₂O₅-Nb₂O₅-Ta₂O₅ system and properties of ScNb_2−2xTa_2xVO₉ phases were studied by X-ray phase analysis, optical and radio spectroscopy. A continuous series of solid solutions was shown to exist at 0≤x≤1. V(IV) centers with different crystallographic surrounding were detected for all the considered compositions. A correlation between the number of V(IV) ions and the width of the forbidden gap in the solid solutions was found.     

Multilayer optics for XUV spectral region: technology fabrication and applications

We present research investigations in the field of multilayer optics in X-ray and extreme ultra-violet ranges (XUV), aimed at the development of optical elements for applications in experiments in physics and in scientific instrumentation. We discuss normal incidence multilayer optics in the spectral region of “water window”, multilayer optics for collimation and focusing of hard X-ray, multilayer dispersing elements for X-ray spectroscopy of high-temperature plasma, multilayer dispersing elements for analysis of low Z-elements. Our research pays special attention to optimization of multilayer optics for projection EUV-lithography (ψ-13nm) and short period multilayer optics.     

Plasmon resonance in a nanosphere

The phenomenon of plasmon resonance in a nanosphere and a nanospheroid is considered. As is known, this phenomenon does not depend explicitly on the size of these nanoparticles. However, it is shown that, actually, the resonance conditions are determined by the diameter of the nanosphere and by the length of the major axis of the nanospheroid.     

Surface polaritons and plasmons: Spontaneous emission from an atom near a small body

The results of experiments, in which the probability of spontaneous Raman scattering from a molecule adsorbed at the surface of a silver nanoparticle was found to grow by 14 and more orders of magnitude, are interpreted. The molecule occurs in the field of a surface plasmon, which accounts for an increase in the local field strength and the density of states by 12–13 orders of magnitude. An additional increase by 1–2 orders of magnitude is explained by the antenna effect of a pair of nanoparticles, one being ultimately small and the other, sufficiently large to serve a receiving-transmitting antenna.     

Model of a disk magnetohydrodynamic channel using pure inert gases and Faraday current commutation

The purpose of this experiment was to find a way to increase the effective conductivity in a nonequilibrium MHD channel. The working material used was inert gas without admixtures of alkali metals. The experiment was carried out in a disk MHD channel coupled to a shock tube, with radial expansion of the gas and an axial magnetic field. An inset was located in a sector of the disk channel with electrodes, to which a load was connected to extract power into an external circuit. Voltage-current characteristics were recorded in this experiment along with the structure of luminous nonuniformities. The results of the experiment showed that as ionization instabilities develop, the effective conductivity of the plasma increases with increasing magnetic induction, and the extracted power density for fields above critical turns out to be roughly 30% higher than that calculated by assuming that the conductivity is a constant. Zh. Tekh. Fiz. 67, 12–15 (December 1997)     

Influence of the Structure of Cetyltrimethylammonium Bromide Based Microemulsions on Base Hydrolysis of Carboxylic Acid Esters

The structure of water/cetyltrimethylammonium bromide/n-butanol/hexane microemulsions was studied by conductometry, viscometry, and Fourier transform ¹H NMR spectroscopy with pulse magnetic field gradient. The regions of phase inversion from inverse micelles in hexane through a bicontinual structure to a dispersion of normal micelles in water were determined. The influence of the structure of the microemulsions on the rate of hydrolysis of carboxylic acid p-nitrophenyl esters was analyzed. The hydrolysis rate constants considerably increase in going from inverse to normal microemulsions.     

Hydrolysis of phosphorus acid esters in the sodium bis(2-ethylhexyl)sulfosuccinate—<Emphasis Type="Italic">n</Emphasis>-nonane—polyethylene glycol—water supramolecular system before and after the percolation threshold

The kinetics of alkaline hydrolysis of O-ethyl O-p-nitrophenyl chloromethylphosphonate in a sodium bis(2-ethylhexyl)sulfosuccinate—n-nonane—polyethylene glycol—water reverse micellar system was studied in a wide range of concentrations of the surfactant and water. The sign of the catalytic effect of micelles is inverted in the presence of the polymer. A sharp change in the apparent rate constant of hydrolysis of the phosphonate was found in a region of the temperature percolation threshold. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 60–67, January, 2007.     

Enhancement of Raman scattering for an atom or molecule near a metal nanocylinder: quantum theory of spontaneous emission and coupling to surface plasmon modes

An analytic expression for the electromagnetic enhancement of the spontaneous emission rate and Raman scattering cross-section for an excited atom or molecule in close proximity to a metal nanocylinder has been derived by quantum theory. Coupling of the atomic or molecular optical radiation into the TM0 surface plasmon mode of the nanocylinder results in reradiation by the cylinder, a process that is most efficient when the incident radiation is linearly polarized, with the electric field oriented parallel to the axis of the nanocylinder. For a silver cylinder having a radius and length of 5 and 20 nm, respectively, the enhancement in the spontaneous emission rate is >10(7) for variant Planck's over 2pi omega0 approximately 2.4 eV (lambda=514 nm), which corresponds to an increase of approximately 10(14) in the Raman scattering cross section. This result, as well as the prediction that the atomic dipole generates broadband, femtosecond pulses, are in qualitative agreement with previously reported experiments involving metal nanoparticle aggregates. The theoretical results described here are expected to be of value in guiding future nonlinear optical experiments in which carbon nanotubes or metal nanowires with controllable physical and electrical characteristics are patterned onto a substrate and coupled with emitting atoms or molecules.