Temperature Dependence of Isotope Effects in Uranium Chemical Exchange Reactions

The Effect of Temperature on Uranium Isotope Effects Studied by Cation Exchange Displacement Chromatography

The uranium isotope effect in the exchange system uranyl(VI)-malate ligand at 288–343 K has been studied by ion exchange displacement chromatography. At all temperatures 235U is enriched at the front of the uranium band. The single stage separation coefficient, (e =a – 1), increased from (0.9 ± 0.1)× 10 at 288 K to (2.9 ± 0.3)× 10–4 at 343 K. The equilibrium constant of the isotope exchange rea...

Temperature dependence of the dynamical behavior and temperature-compensation in oscillatory chemical reactions PhD thesis

Temperature-compensated chemical reactions.

Circadian rhythms are daily oscillations in behaviors that persist in constant light/dark conditions with periods close to 24 h. A striking feature of these rhythms is that their periods remain fairly constant over a wide range of physiological temperatures, a feature called temperature compensation. Although circadian rhythms have been associated with periodic oscillations in mRNA and protein ...

Theoretical analysis on the kinetic isotope effects of bimolecular nucleophilic substitution (S(N)2) reactions and their temperature dependence.

Factors affecting the kinetic isotope effects (KIEs) of the gas-phase S(N)2 reactions and their temperature dependence have been analyzed using the ion-molecule collision theory and the transition state theory (TST). The quantum-mechanical tunneling effects were also considered using the canonical variational theory with small curvature tunneling (CVT/SCT). We have benchmarked a few ab initio a...

Temperature dependence of isotope ratios in tree rings.

The stable isotope ratios of carbon, oxygen, and hydrogen have been measured for a German oak in wood samples of roughly three years each, for the years 1712-1954 A.D., and correlated with the existing weather records from England, Basel, and Geneva to evaluate the empirical temperature coefficients. Isotope ratios in a second official oak, measured for the years 1530-1800 A.D., show the cold t...