Application of new types of fibrous sorbents for sampling of dissolved species of heavy metals in natural waters

The article discusses the importance and specific features of the preparatory stages in ecoanalytical monitoring of natural water, aimed to determine the content of heavy metals. A procedure was developed for sampling of dissolved species of heavy metals with sorbents. The influence of humic substances on the sorption of heavy metals was elucidated. The results obtained with the technique suggested are reported.     

Optical third-harmonic generation in one-dimensional photonic crystals and microcavities

The formalism of nonlinear transfer matrices is used to develop a phenomenological model of a cubic nonlinear-optical response of one-dimensional photonic crystals and microcavities. It is shown that third-harmonic generation can be resonantly enhanced by frequency-angular tuning of the fundamental wave to the photonic band-gap edges and the microcavity mode. The positions and amplitudes of third-harmonic resonances at the edges of a photonic band gap strongly depend on the value and sign of the dispersion of refractive indexes of the layers that constitute the photonic crystal. Model calculations elucidate the role played by phase matching and spatial localization of the fundamental and third-harmonic fields inside a photonic crystal as the main mechanisms of enhancement of third-harmonic generation. The experimental spectrum of third-harmonic intensity of a porous silicon microcavity agrees with the calculated results.     

Quantum-chemical study of the spectral properties of stilbene isomers

Calculations of absorption spectra of cis-and trans-forms of stilbene by the quantum-chemical method of intermediate neglect of differential overlap with spectroscopy parametrization were carried out. The electron structure of a stilbene molecule was studied and energy-level diagrams were drawn and analyzed. Rate constants of different photophysical processes occurring in a stilbene molecule after absorption of a photon were calculated in relation to the molecule conformation. On the basis of the obtained results, possible configurations of photoisomer molecules were considered and the most probable configurations of excited stilbene molecules were determined. It was shown how the change in the configurations of cis-and trans-forms of stilbene affects its spectral properties.     

Untersuchung der Strukturunhomogenit?t der Polyurethannetzwerke mittels der Lichtstreuungsmethode

Ohne Zusammenfassung     

Polarization-sensitive correlation spectroscopy of Faraday-effect femtosecond dynamics

Femtosecond dynamics of the Faraday effect is experimentally studied in thin magnetic films by polarization-sensitive correlation spectroscopy.     

Synthesis of metallocene thioketones

Conclusions Previously unknown cymantrene thioketones (thioacetylcymantrene and thiobenzoylcymantrene) and ferrocene thioketones (thioacetylferrocene and thiobenzoylferrocene) have been synthesized.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 869–872, April, 1979.