Disintegration of hydrogen phases in palladium and titanium during irradiation with a synchrotron radiation bunch in the X-ray spectral region

Data from measurements of the disintegration kinetics of hydrogen phases in palladium and titanium during annealing and irradiation with a synchrotron radiation bunch in the X-ray spectral region on the VEPP-3 LIGA Technology station are presented. The hydride phases in palladium and titanium remain stable at sample temperatures of 60°C and irradiation doses of up to 3000 J cm^?3 during irradiation with a synchrotron radiation bunch and start to decompose during sample heating to a temperature of 90–100°C.     

Cycloadducts of fullerene C60 with trolox and tocopherol diazo derivatives: synthesis and antioxidant activity

The antioxidant activity of new cycloadducts, [2H-chromen-2″-yl]carbonylmethano-fullerenes, obtained from fullerene C₆₀ and diazo ketones was quantitatively studied with initiated cumene oxidation as a model reaction.     

The magnetic isotope effect and oxygen isotope selection in chain processes of polymer oxidation

Experimental evidence based on the dependence of molecular oxygen isotope enrichment on the oxygen conversion, temperature and kinetic chain length indicate that, in chain processes of polymer oxidation, the elementary, reactions (recombination or disproportionation) of peroxy radicals are responsible for the selection of both ¹⁷O and ¹⁸O isotopes. The ¹⁷O selection is induced by a magnetic isotope effect and is sensitive to the molecular dynamics, while ¹⁸O selection is due to a classical mass-dependent isotope effect and is much less effective.     

Quenching of electronically excited Ln3+* ions by C60 fullerene

Quenching of electronically excited states of Ln^3+* ions generated upon photoexcitation of toluene solutions of Ln(acac)₃·H₂O (Ln = Tb, Eu) complexes by C₆₀ fullerene at 293 K was detected and investigated. The dependences of quenching efficiency on C₆₀ concentration obtained from data on the decrease in the photoluminescence intensity and Ln^3+* lifetimes obey the Stern-Volmer law. Quenching is due to inductive-resonant energy transfer from Ln^3+* to C₆₀ fullerene. The bimolecular rate constants for quenching, the overlap integrals of the Ln^3+* photoluminescence spectra with the C₆₀ absorption spectra, and the critical energy transfer distances were determined. No sensitized luminescence of C₆₀ in the system studied was detected. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 921–925, June, 2006.     

Fullerene C<Subscript>60</Subscript> as a superefficient quencher of singlet exited states of polycyclic aromatic hydrocarbons

Quenching of fluorescence of polycyclic aromatic hydrocarbons (PAH), namely, naphthalene, anthracene, 9,10-diphenylanthracene, 9,10-dibromoanthracene by C₆₀ fullerene in ethylbenzene at 293 K was found and investigated. The phenomenon is characterized by abnormally high values of bimolecular rate constants for quenching (k _bim = (0.18–6.78)·10¹² L mol⁻¹ s⁻¹) determined from the Stern—Volmer dependence of the PAH fluorescence intensity on the C₆₀ concentration and occurs through the inductive-resonance (dominant channel) and exchange-resonance (minor channel) energy transfer from ¹PAH* to C₆₀. The overlap integrals of the PAH fluorescence spectra with the C₆₀ absorption spectrum and the critical energy transfer distances were calculated. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 432–436, March, 2007.     

Structure and bifurcations of plane shock waves in a vibrationally excited gas with an external pumping source

The structure of the density profiles in stationary plane shock waves in a vibrationally excited gas is investigated. For self-similar solutions a bifurcation diagram is plotted in the parametric “traveling wave velocity—degree of nonequilibrium” plane. The bifurcation boundaries of the domains of existence of the structures of different types are analytically derived. It is shown that weak plane shock waves are unstable, accelerate, and break down into a sequence of pulses or-at a fairly high pumping rate-waves with nonzero asymptotics, whose amplitude and propagation velocity are independent of the initial disturbance and are determined by the parameters of the medium itself.     

ESR spectral determination of the structural organization of smectic phase states of a cupric Schiff base complex

ESR spectroscopy was used to study different smectic phases of a mesogenic cupric Schiff base complex. A new low-symmetry (triclinic) syngony of a highly organized smectic phase was discovered beyond the range of the De Vries system. Parameters characterizing the structure of this phase were obtained.Kazan Physics Technology Institute. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 6, pp. 65–69, November–December, 1989.     

Temperature profile at the front of a shock wave propagating in a vibrationally excited stationary nonequilibrium gas

The variation of the temperature profile in a shock wave propagating in a vibrationally excited gas is studied as a function of the wave velocity and the degree of nonequilibrium of the gas.