The formation of the superheavy hydrogen isotope <Superscript>6</Superscript>H in the absorption of stopped π<Superscript>−</Superscript>-mesons by nuclei

An experimental search for the superheavy hydrogen isotope ⁶H was conducted through studying the absorption of stopped π^?-mesons by ⁹Be and ¹¹B nuclei. A structure in the missing mass spectrum caused by the resonance states of ⁶H was observed in three reaction channels, namely, ⁹Be(π^?, pd)X, ¹¹B(π^?, d³He)X, and ¹¹B(π^?, p⁴He)X. The parameters of the lowest state E_r=6.6±0.7 MeV and Γ=5.5±2.0 MeV (E_r is the resonance energy with respect to the disintegration into the triton and three neutrons) are evidence that ⁶H is a more weakly bound system than ⁴H and ⁵H. Three excited states of ⁶H were observed. Their resonance levels (E_1r=10.7±0.7 MeV, Γ_1r=4±2 MeV, E_2r=15.3±0.7 MeV, Γ _2r=3±2 MeV, and E_3r=21.3±0.4 MeV, Γ_3r=3.5±1.0 MeV) are energetically capable of disintegrating into six free nucleons.     

Alkoxylation of 1,2-Bis(methylchlorosilyl)ethylenes and -Acetylenes

Reactions of a series of 1,2-bis(methylchlorosilyl)ethylenes and -acetylenes Me_nCl_{3 - n}Si-Z-SiCl_{3 - n}Me_n (Z = CH = CH, CC; n = 0-2) with ethanol and acetoxime were studied. Novel alkoxy- and isopropylideneaminooxysilanes were obtained and characterized. A relation was found between the activity of Si-Cl bonds in the reactions studied and the structure of the carbon-carbon bridge.     

Effect of Substituents on the Silicon Atom on Etherification of Organochlorosilanes with Ethanol

The kinetics of etherification of organochlorosilanes with various substituents on the silicon atom with ethanol were studied. The etherification rate is mostly controlled by the inductive constants of the substituents and increases as the electron-acceptor power of the substituents increases. The ^* value in the Taft equation for etherification of organochlorosilanes with ethanol was determined.     

Quantum-chemical calculations of NMR chemical shifts of organic molecules: VIII. Solvation effects on 15N NMR chemical shifts of nitrogen-containing heterocycles

Effect of solvation on the accuracy of DFT quantum-chemical calculations of ¹⁵N NMR chemical shifts of pyrrole, N-methylpyrrole, and pyridine was studied. The use of continuum model is sufficient to obtain consistent theoretical σ_N values for weakly polar aprotic solvents, whereas solvation effects in strongly polar and protic solvents should be taken into account in the explicit form.     

Experimental and numerical investigation into the supersonic flow of a weakly ionized plasma around a dihedral angle: Magnetohydrodynamic control of the flow pattern and heat fluxes toward the wall

The results of experimental and numerical investigations into magnetohydrodynamic actions on the supersonic flow of a weakly ionized xenon plasma around a wedge are presented. The conditions of numerical simulation correspond to the conditions of experiments carried out on the Bol’shaya shock tube at the Ioffe Physicotechnical Institute.     

Semiclassical asymptotics and statistical properties of Gaussian packets for the nonstationary Schrödinger equation on a geometric graph

The propagation of localized quantum packets on a geometric graph is described. The evaluation of the number of packets for large times turns out to be related to some problems in number theory. Dedicated to the memory of V. A. Geyler