Gamma resonance spectroscopic study of compounds containing the π-allylirontricarbonyl group

The gamma resonance (GR) spectra of a series of -allylirontricarbonyl compounds and -cyclopentadienyldicarbonyl complexes of iron have been recorded. The relationship between the GR spectra of these compounds and the electronic structure of the iron atom in the complexes has been examined. It has been shown that tetrahydrofuran, benzene, and acetonitrile do not react with -allylirontricarbonyl chloride, whereas dimethylformamide decomposes it with the formation of high-spin complexes of iron. The formation of the [-C₃H₅Fe(CO₃)]^– anion in the reduction of [C₃H₅Fe(CO₃)]I by naphthalene-sodium in benzene has been confirmed.     

Breakup of gas bubbles in a liquid by shock waves

The nature of the propagation of shock waves in various media is related to the characteristics of the latter, including their compressibility, thermophysical properties, the presence of multiple phases, etc. The structure of a shock wave varies appreciably as a function of the properties of the medium. The most significant property of a liquid mixture with gas bubbles is the compressibility of the latter under the influence of an externally applied pressure, for example, in a shock wave propagating in the liquid—gas medium. The transfer of momentum and energy between phases and the pressure variation behind the wave depends on the behavior of the gas bubbles behind the shock front.     

Acceleration ability of high explosives and their mixtures with fuel additives. 1. Assessment by the M-40 method

The relationship between the chemical composition of the detonation products and the acceleration ability of explosives is considered. Based on theoretical and experimental studies, it is concluded that, at volumetric energy content, the most important parameter is the average atomicity of the molecules constituting the detonation products. Among the CHNOF-containing explosives, groups with high acceleration ability were identified. The experimental results on the acceleration ability obtained using the M-40 method are reported for mixtures of dispersed Al with HEs with different oxygen balance and for mixtures of HMX-based HE with Al, Mg, Y, Ta, ZrH₂. An analysis of the acceleration ability on the charge density for BTNEN and mixtures thereof with Al made is possible to estimate the degree of conversion of the energy of combustion of Al under the gasdynamic conditions typical of the M-40 method, which turned out to be 20–40%.     

Variable spectral filter based on optically saturated selective reflection

We have studied the selective reflection from glass-rubidium vapor interface at a large incidence angle in pump-probe experiment. The linear reflectivity can be more than 0.9 in a narrow spectral range (several GHz) at the blue side of the atomic resonance. The effect can be called the reduced total selective reflection. The reflectivity has been decreased two times due to the optical saturation. The obtained results can be used to develop a variable optical filter or optical switcher. Our estimations show that switching time can be less than the natural lifetime of the excited state. We suggested a multi-reflection scheme to increase the contrast of the variable spectral filter.     

Tunable single-frequency CW Cr<Superscript>2+</Superscript>:CdSe laser

Continuous tuning of the lasing wavelength from 2350 to 3450 nm in the cw Cr²⁺:CdSe laser is demonstrated. It is shown that the laser efficiently operates at a wavelength of 3.28 μm, which is promising for the methane optical frequency standard. The single-frequency mode of the laser with a lasing linewidth not exceeding 60 MHz is implemented in this spectral range.     

Supercritical isopropanol as a reducing agent for inorganic oxides

Preparative methods for the reduction of simple and complex metal oxides by supercritical isopropanol (SCI) were developed. Procedures for effective work with SCI under usual laboratory conditions were suggested. Optimum reaction conditions (temperature and pressure) and reagent ratios for reactions between SCI and metal oxides were found. Disperse oxides coated by fine-dispersity metals that could be used as catalysts were prepared. Simple methods for obtaining metal nanoparticles by the reduction in situ of metal oxide nanoparticles stabilized in polyethylene and synthetic silica (opal) matrices with SCI were developed.     

Promising avenues of research in nanoscience: chemistry of semiconductor nanoparticles

The state-of-the-art in the field of research on semiconductor nanoparticles is analyzed; cadmium chalcogenide nanoparticles are considered in most detail. Emphasis is placed on the methods of synthesis and on control of the size, composition, and structure of semiconductor nanoparticles — “quantum dots”. The state of the surface plays a significant role in determining the properties of nanoparticles. Organized nanostructures comprised of quantum dots are considered. The properties of semiconductor nanoparticles are described. Prospects for applications of semiconductor nanomaterials are discussed. Dedicated to Academician V. I. Minkin on the occasion of his 70th birthday. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 811–836, April, 2005.