Linear optical bullets

We describe a class of spatio-temporal optical pulses that spread neither spatially nor temporarily in linear dispersive media over long propagation distances. These new spatio-temporal pulses, referred to as linear optical bullets, can have any spatio-temporal profile and temporal width, and they carry a finite amount of energy. We also discuss in detail a technique for the experimental realization of linear optical bullets.     

Fractal analysis of RF signals scattered by small-scale ionospheric irregularities

The fractal dimension as a characteristic of an experimental data series is considered. The correlation integral method is used for dimension calculation. It is shown that by the fractal dimension one can identify a variety of ionospheric processes even when the conventional spectral analysis fails. It is found that the realizations corresponding to volume scattering by natural and artificial irregularities have finite dimension, which is significantly different. A technique for preparing experimental data to be processed by the correlation integral method is developed. The influence of the data sampling rate and signal-to-noise ratio on the dimension is analyzed.Radioastronomical Institute, Ukrainian Academy of Sciences, Khar'kov. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 38, No. 6, pp. 557–565, June, 1995.     

Quantum-Chemical Investigation of the Mechanism of Transfer of Fluorine in the Reaction of F‐TEDA‐BF4 with Dimethylenebicyclo[3.3.1]nonane

The mechanism of the reaction of the N-fluoro reagent FTEDABF₄ with dimethylenebicyclo[3.3.1]nonane was investigated by the semiempirical PM3 SCF MO method using the Cramer–Truhlar SM5.42R solvation model. It was shown that the mechanism of addition of the fluorine corresponds to classical S _N 2 nucleophilic substitution involving single-electron transfer synchronous with the cleavage–formation of C—F and N—F bonds.     

Electrical and Spectral Properties of Complexes of Pyridine N-Oxide Derivatives with Iron Trichloride

Complexes (1 : 2) of iron trichloride with N-oxides of pyridine, picolines, and 2,6-lutidine were studied by optical spectroscopy, dielectrometry, and conductometry. In solid complexes, three crystalline phases are in equilibrium; the nuclei of each of these phases can be detected in the oily state. The enthalpies of the coordination bonds are different in different phases. One of the phases of the 3-picoline N-oxide complex shows a strong orientation disorder; disappearance of the short-range order causes weakening of the coordination bonds by 1.6 kcal. The thermal motion of free base molecules in two phases of the 2,6-lutidine N-oxide complex is gaslike. In the solid phase of this complex, there is a strong distribution of the relaxation frequencies; the mean relaxation frequency is close to 220 Hz. Upon irradiation of the complexes with solar or UV light, specific coloration centers can form. Weak alternating electric fields initiate in some compounds reversible chemical reactions. The intermolecular and charge equilibria in the compounds are very labile; the energy of generation of the low-temperature electrical conductivity in them is close to 0.9 eV.     

New heterocyclic sym-triazolopyrimidinium systems — Quinoline,pyridazine, and phthalazine derivatives

Pyrimido[1′,2′:1,5]-sym-triazolo[4,3-b]pyridazinium, pyrimido[1′,2′:1,5]-sym-triazolo-[4,3-b]phthalazinium, and pyrimido[1′,2′:1,5]-sym-triazolo[4,3-a]quinoliniumsalt derivatives were obtained by condensation of 3-amino-sym-triazolo[4,3-b]pyridazinium, 3-amino-sym-triazolo[3,4-a]phthalazinium, and 1-amino-sym-triazolo[4,3-a]quinolinium salts with β-diketories and 1,1,3,3-tetraethoxypropane. The structures of the reaction products were confirmed by the P MR spectra.     

Synthesis and characterization of novel carbene complexes of phosphorus(V) fluorides with potential liquid-crystalline properties

A series of novel push–pushI and push–pullII carbene-stabilized complexes of phosphorus(V) fluorides bearing substituents with liquid-crystalline properties were synthesized by the oxidative addition of difluoroamines to phosphorus(III) halides. These octahedral complexes were characterized by NMR spectroscopy and X-ray analysis.