The isotope effect of the solvent in the chemiluminescent oxidation of uranium(IV) by the products of the interaction of XeO3 with H2O2 in aqueous sulfuric acid

Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1341–1342, July, 1994.     

Chemihiminescence by the interaction of XeO3 and the products of photolysis of uranyl solutions in sulfuric acid

Using the chemiluminescence oxidation of U(IV) and H₂O₂ with xenon trioxide as a model, it has been found that during the photolysis of solutions of UO₂SO₄ in sulfuric acid in the absence of any organic compounds, the accumulation of U(SO₄)₂ and H₂O₂ takes place as a result of the reaction of the primary products of the photoreduction of uranyl ion,i.e., UO₂ ⁺ and the OH radical.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 751–754, April, 1994.The work was financially supported by the Russian Foundation for Basic Research, Project 93-03-12291.     

Radiothermoluminescence of polycrystalline high-temperature superconducting YBa2Cu3O6.94, EuBa2Cu3O6.9, and SmBa2Cu3O6.9 samples

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, p. 1934, August, 1991.     

Temperature Quenching of Uranyl Ion Photoluminescence in Frozen Deuterated Aqueous Solutions of Sulfuric Acid

The effect of solvent deuteration revealed as a difference in the shape of temperature dependence curves for the lifetime of uranyl ion in the electronically excited state () upon warming H₂SO₄ solutions in ₂ and D₂SO₄ solutions in D₂O frozen at 77 K was detected. The value of in the case of D₂SO₄ was shown to be shorter in the glassy solution than in the polycrystalline sample, whereas the reverse was observed in frozen H₂SO₄ solutions. This effect was explained by dissimilar occurrence of phase transitions in H₂SO₄ and D₂SO₄ solutions, as well as by a decrease in the probability of nonradiative deactivation of *(UO²⁺ ₂) adsorbed on the surface of the crystal hydrate D₂SO₄·4D₂O as compared with that on the surface of the crystal hydrates H₂SO₄·4H₂O and H₂SO₄·6.5H₂O.     

Autoacceleration of the free-radical chain luminescent oxidation of U(IV) with xenon trioxide in aqueous HClO<Subscript>4</Subscript>

Autoacceleration is observed in the chemiluminescent radical chain oxidation of U(IV) with xenon trioxide in aqueous perchloric acid in a Teflon (not conventional glass) reactor. The decay of chemiluminescence accompanying the reaction between U(IV) and XeO₃ in the case of excess oxidizer obeys a first-order kinetic equation only at low U(IV) concentrations of 10^?5–10^?6 mol/l. Autoacceleration takes place at comparatively high reactant concentrations, when the contribution from the heterogeneous loss of radicals on the reactor walls into chain termination is comparatively small and the role of degenerate chain branching reactions is significant. It is inferred that a critical phenomenon rare for liquid-phase radical chain processes takes place in U(IV) oxidation with xenon trioxide: a comparative small increase in the reactant concentrations causes this chemiluminescent redox process to pass from the quasi-steady-state regime to autoacceleration.