Preparation of tritium-labelled oleic acid and prostaglandins E2 and F1α. A study of the process of including tritium in molecules of unsaturated fatty acids and prostaglandins

[³H]Prostaglandin E₂ and [³H]prostaglandin F_1a have been obtained with the aid of heterogeneous catalytic isotope exchange with gaseous tritium in solution. The distribution of the tritium in the labelled unsaturated fatty acids and prostaglandins has been studied.Institute of Molecular Genetics, Academy of Sciences of the USSR, Moscow. M. M. Shemyakin Institute of Bioorganic Chemistry, Khimiya Prirodnykh Soedinenii, No. 2, pp. 148–157, March–April, 1980.     

Observation of Quantum Beats of Two-Photon-Excited States of Xe upon Photoionization

Optics and Spectroscopy - Ionization of coherently two-photon-excited superposition of 4f states of Xe in a supersonic atomic beam is studied by means of femtosecond pump–probe spectroscopy....     

The Optimal Pair of Rydberg Alkali-Metal Atoms in the Nonsymmetric Penning Ionization Processes

Optics and Spectroscopy - Features of Penning ionization in cold gaseous media of Rydberg alkali-metal atoms have been investigated. In contrast to the hydrogen atom, the corresponding...     

New Adamantane Derivatives with NO-Generating Fragment

An approach to the synthesis of adamantane derivatives with NO-generating fragment containing nitroxy group has been developed. 1-Aminoadamantane, memantine, and adamantanecarboxylic acid have been used as initial compounds. The prepared compounds have shown ability to generate nitric oxide in a system mimicking biological reactions of nitro group reduction.     

Autoionization of an ultracold Rydberg gas through resonant dipole coupling

We investigate a possible mechanism for the autoionization of ultracold Rydberg gases, based on the resonant coupling of Rydberg pair states to the ionization continuum. Unlike an atomic collision where the wave functions begin to overlap, the mechanism considered here involves only the long-range dipole interaction and is in principle possible in a static system. It is related to the process of intermolecular Coulombic decay (ICD). In addition, we include the interaction-induced motion of the atoms and the effect of multi-particle systems in this work. We find that the probability for this ionization mechanism can be increased in many-particle systems featuring attractive or repulsive van der Waals interactions. However, the rates for ionization through resonant dipole coupling are very low. It is thus unlikely that this process contributes to the autoionization of Rydberg gases in the form presented here, but it may still act as a trigger for secondary ionization processes. As our picture involves only binary interactions, it remains to be investigated if collective effects of an ensemble of atoms can significantly influence the ionization probability. Nevertheless our calculations may serve as a starting point for the investigation of more complex systems, such as the coupling of many pair states proposed in [P.J. Tanner et al., Phys. Rev. Lett. 100, 043002 (2008)].     

Analysis of Fokker-Planck type stochastic equations with variable boundary conditions in an elementary process of collisional ionization

The diffusion model of ionization of Rydberg atoms in single collisions is formulated. The solution of kinetic equations describing nonstationary diffusion processes is discussed. Methods of analytical calculation of the effective times for the development of ionization in phase regions with moving boundaries are presented. An analytical method, going back to Weisskopf, for determining the corresponding cross sections for impact ionization in the adiabatic approximation is described. A numerical scheme for solving problems of stochastic movement of a Rydberg electron inside a Coulomb condensation of levels under conditions of time-variable ionization boundaries and region of development of stochastic instability is developed.