Sono-Photocatalytic Degradation of 4-Clorophenol in Aqueous Solutions

Russian Journal of Physical Chemistry A - The kinetic patterns of oxidative processes involving highly reactive oxygen-containing radicals generated in situ in the aqueous medium affected by...     

Calibration of Temperature from the Fluorescence Spectra of Lead–Fluoride Glass Doped with Erbium

Optics and Spectroscopy - Multivariate methods are applied to the calibration of temperature in the range from 299 to 423 K for the green fluorescence spectra of erbium in...     

Stark coefficients for highly excited rovibrational states of H2O

Quantum beat spectroscopy is combined with triple-resonance vibrational overtone excitation to measure the Stark coefficients (SCs) of the water molecule for 28 rovibrational levels lying from 27,600 to 41,000 cm(-1). These data provide a stringent test for assessing the accuracy of the available potential energy surfaces (PESs) and dipole moment surfaces (DMSs) of this benchmark molecule in this energy region, which is inaccessible by direct absorption. SCs, calculated using the combination of a high accuracy, spectroscopically determined PES and a recent ab initio DMS, are within the 1% accuracy of available experimental data for levels below 25,000 cm(-1), and within 4.5% for coefficients associated with levels up to 35,000 cm(-1). However, the error in the computed coefficients is over 60% for the very high rovibrational states lying just below the lowest dissociation threshold, due, it seems, to lack of a high accuracy PES in this region. The comparative analysis suggests further steps, which may bring the theoretical predictions closer to the experimental accuracy.     

Control over the space-time structure of electron beams by high-intensity femtosecond laser radiation

The space-velocity distribution of electrons propagating in vacuum can be deformed by the ponderomotive potential produced by high-intensity femtosecond laser pulses, which makes it possible to subsequently separate such electrons from the initial beam. It is shown that optical modification of electron beams with kinetic energies on the order of 100 eV by femtosecond laser radiation with an intensity from 10¹⁴ to 10¹⁸ W/cm² makes it possible to form electron beams with a duration on the order of 50–100 fs. Examples of optical control over the shape of electron beams, based on deflection, reflection, focusing, and splitting of electron beams, are considered.     

Correction to the Article “Deformation of Plates of Small Condensers and Belinskii's Problem”

A corrected proof is given of Lemma 4.1 of the above-mentioned article.     

Femtosecond laser photoemission microscopy of capillary nanotips with ultrahigh spatial resolution

A nanolocalized electron beam emitted from silicon nanotubes has been used to image the aperture of a quartz capillary with a channel diameter of 100 nm. An analogous nickel-coated capillary was used as a tip for imaging deposited organic nanostructures by means of femtosecond laser photoelectron projection microscopy (LPPM). Organic nanocomplexes deposited onto the tip surface change the dependence of the photoelectron response signal on the energy density of probing femtosecond laser pulses. An analysis of the LPPM images of capillary nanotips shows that the spatial resolution achieved in these experiments is on a level of 5 nm.     

On the Geometric Definition of Quasiconformality

Siberian Mathematical Journal - Considering a homeomorphism of the plane onto itself, we prove that the criterion of quasiconformality is the presence of an upper bound for the...     

Ned sets on a hyperplane

Under study are the sets in ℝ ⁿ (NED sets) each of which does not affect the conformal capacity of any condenser with connected plates disjoint from this set. These sets are removable singularities of quasiconformal mappings, which explains our interest in them. For compact sets on a hyperplane we obtain a geometric criterion of the NED property; we point out a simple sufficient condition for an NED set in terms of the connected attainability of its points from its complement in the hyperplane. For compact sets on a hypersphere we obtain a criterion for an NED set in terms of the reduced module at a pair of points in its complement. We establish that a compact set on a hypersphere S, removable for the capacity in at least one spherical ring concentric with S and containing S, is an NED set.     

Observation of coherent optical phonons excited by femtosecond laser radiation in Sb films by ultrafast electron diffraction method

The generation of coherent optical phonons in a polycrystalline antimony film sample has been investigated using femtosecond electron diffraction method. Phonon vibrations have been induced in the Sb sample by the main harmonic of a femtosecond Ti:Sa laser (λ = 800 nm) and probed by a pulsed ultrashort photoelectron beam synchronized with the pump laser. The diffraction patterns recorded at different times relative to the pump laser pulse display oscillations of electron diffraction intensity corresponding to the frequencies of vibrations of optical phonons: totally symmetric (A _1g ) and twofold degenerate (E _g ) phonon modes. The frequencies that correspond to combinations of these phonon modes in the Sb sample have also been experimentally observed.