Природа эффекта рассогласования частот прецессии ядер -=SUP=-129-=/SUP=-Xe и -=SUP=-131-=/SUP=-Xe при спин-обменной накачке атомами щелочного металла

The effect of precession-frequency mismatch between ^129Xe and ^131Xe xenon-isotope nuclei, which arises under spin-exchange pumping by optically oriented alkali-metal (Cs) atoms and affects the characteristics of measuring and navigation devices based on balanced Schemes with spin-exchange pumping of xenon isotopes, has been investigated. An attempt to explain this effect has been made, and methods for its minimization and elimination have been proposed and experimentally verified.

The origin of the measured chemical shift of 129Xe in UiO-66 and UiO-67 revealed by DFT investigations

The NMR chemical shift of the xenon isotope 129Xe inside the metal–organic frameworks (MOFs) UiO-66 and UiO-67 (UiO – University of Oslo) has been investigated both with density functional theory (DFT) and in situ high-pressure 129Xe NMR measurements.

The iodine–plutonium–xenon age of the Moon–Earth system revisited

Iodine–plutonium–xenon isotope systematics have been used to re-evaluate time constraints on the early evolution of the Earth–atmosphere system and, by inference, on the Moon-forming event. Two extinct radionuclides ( 129 I, T 1/2 =15.6 Ma and 244 Pu, T 1/2 =80 Ma) have produced radiogenic 129 Xe and fissiogenic 131−136 Xe, respectively, within the Earth, the related isotope fingerprints of which are seen in the compositions of mantle and atmospheric Xe. Recent studies of Archaean rocks suggest that xenon atoms have been lost from the Earth's atmosphere and isotopically fractionated during long periods of geological time, until at least the end of the Archaean eon. Here, we build a model that takes into account these results. Correction for Xe loss permits the computation of new closure ages for the Earth's atmosphere that are in agreement with those computed for mantle Xe. The corrected Xe formation interval for the Earth–atmosphere system is Ma after the beginning of Solar System formation. This time interval may represent a lower limit for the age of the Moon-forming impact.