Kinetics of the hydroxylation of N-picryl-4-[4-(dimethylamino)styryl]pyridinium salts by molecular oxygen in acetonitrile

The reactions of N-picryl-4-[4-(dimethylamino)styryl]pyridinium salts with molecular oxygen in the presence of 4-[4-(dimethylamino)styryl]pyridine (DASP) in acetonitrile proceeds with the formation of DASP picrate. The reactions are first-order relative to the salt cation, molecular oxygen, and the catalyst (DASP). L. M. Litvinenko Institute of Physical Organic and Coal Chemistry, National Academy of Sciences of Ukraine, 70 R, Lyuksemburg ul., Donetsk 340114, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 34, No. 5, pp. 286–289, September–October, 1998.     

The Influence of Signal Polarization on Quantum Bit Error Rate for Subcarrier Wave Quantum Key Distribution Protocol

In this paper, we consider the influence of a divergence of polarization of a quantum signal transmitted through an optical fiber channel on the quantum bit error rate of the subcarrier wave quantum key distribution protocol. Firstly, we investigate the dependence of the optical power of the signal on the modulation indices’ difference after the second phase modulation of the signal. Then we consider the Liouville equation with regard to relaxation in order to develop expressions of the dynamics of the Stokes parameters. As a result, we propose a model that describes quantum bit error rate for the subcarrier wave quantum key distribution depending on the characteristics of the optical fiber. Finally, we propose several methods for minimizing quantum bit error rate.     

Investigation of the effect of large-scale shell asymmetry on Iskra-5 target operation

Experiments designed to investigate the effect of a controlled large-scale asymmetry of a shell containing deuterium-tritium fuel on the shell compression and neutron production under indirect (x-ray) action are performed on the Iskra-5 laser fusion device. The uniformity of the x radiation near the target is not worse than 3%, and the shell asymmetry is varied from 30 to 100%. The observed decrease of the experimental neutron yield as compared with experiments using symmetric targets is in satisfactory agreement with two-dimensional calculations. Pis’ma Zh. éksp. Teor. Fiz. 67, No. 3, 161–165 (10 February 1998)     

Generation of the line radiation of argon added to DT gas in Iskra-5 experiments

The first experiments measuring the density of a compressed deuterium and tritium mixture in microtargets of indirect irradiation (x-ray targets) were performed at the Iskra-5 facility. The density was determined according to the broadening of the lines of hydrogen-and helium-like argon added to the DT gas as a diagnostics material. A series of three experiments was performed with x-ray targets in which the central capsule filled with a DT + Ar mixture over a range of shell thicknesses. In two of the experiments, argon emission spectra were recorded and the density of the compressed gas was determined. For a microtarget approximately 280 μm in diameter with a wall approximately 7 μm thick, an analysis of the experimental results yielded an estimated density in the compressed gas of ∼1 g/cm³. Gas-dynamic calculations using the SNDA (spectral nonequilibrium diffusion with absorption) program show that argon emission takes place just after reaching maximum temperature, but much sooner than maximum compression. The results of a calculation for an experiment with low relative Ar concentration are in overall agreement with the experimental data. Additional investigations are needed to interpret experiments at a relatively high concentration. Zh. éksp. Teor. Fiz. 114, 837–848 (September 1998)     

Effect of molecular oxygen on the kinetics and mechanism of the reaction of 2-bromo-1-ethylpyridinium bromide with triethylamine in acetonitrile

The nucleophilic aromatic substitution of bromine into 2-bromo-1-ethylpyridinium bromide (I) in its reaction with triethylamine (II) is accompanied by subsequent oxidation of the intermediates by molecular oxygen dissolved in acetonitrile. The following reaction products were identified: 1-ethyl-2-pyridone, triethylamine N-oxide, and the hydrobromide salt of triethylamine. The reaction kinetics was studied with reagents ratios     

Kinetic and thermodynamic interpretation of the reversible reaction of 2,4,6-trinitrochlorobenzene with 4-[4-(dimethylamino)styryl]pyridine in acetonitrile

The energetic and activation parameters for the reversible reaction of 2,4,6-trinitrochlorobenzene with 4-[4-(dimethylamino)styryl]pyridine in acetonitrile were determined. The rate constants for the forward and reverse reactions were found to be equal at 300 K. L. M. Litvinenko Institute of Physical Organic and Coal Chemistry, National Academy of Sciences of Ukraine, R. Lyuksemburg St., 340114 Donetsk. Ukraine. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 33, No. 3, pp. 149–152, May–June, 1997.     

Compression and heating of spherical fusion targets by indirect (x-ray) drive on the Iskra-5 facility

Experiments have been carried out using the Iskra-5 facility in order to study the behavior of x-ray targets in response to a highly symmetric x-ray field. Results are presented of experiments using targets in the form of a spherical copper hohlraum coated with gold on the inside, with six laser entrance holes and a glass microtarget filled with DT gas located at the center. In some experiments the central capsule was coated with a plastic ablator layer of varying thickness. An analysis of the experimental results showed that on the whole, they are satisfactorily described by spherically symmetric gasdynamic calculations. Zh. éksp. Teor. Fiz. 114, 155–170 (July 1998)     

Kinetics and Quantum-Chemical Modelling of the Arylation of Aniline and Piperidine by N-Polynitroarylpyridinium Salts

N-Picryl-4-[4-(dimethylamino)styryl]pyridinium salt anions catalyze S _NAr reactions with aniline in acetonitrile. The anion activity increases with increasing basicity. A stepwise substitution mechanism involving the salt anions is confirmed by MNDOd and PM3 semiempirical calculations of the change in free energy of the individual reaction steps of N-polynitrophenylpyridinium chlorides with aniline and piperidine.