The thorium nucleus with mass number A = 229 has attracted much interest because its extremely low lying first excited isomeric state at about 8 eV opens the possibility for the development of a nuclear clock. However, neither the exact energy of this nuclear isomer nor properties, such as nuclear magnetic dipole and electric quadrupole moment are known to a high precision so far. The latter can be determined by investigating the hyperfine structure of thorium atoms or ions. Due to its electronic structure and the long lifetime of the nuclear isomeric state, Th 2+ is especially suitable for such kind of studies. In this letter we present a combined experimental and theoretical investigation of the hyperfine structure of the 229 Th 2+ ion in the nuclear ground and isomeric state. A very good agreement between theory and experiment is found for the nuclear ground state. Moreover, we use our calculations to confirm the recently presented experimental value for the nuclear magnetic dipole moment of the thorium nuclear isomer, which was in contradiction to previous theoretical

The parity nonconservation effect on the radiative recombination of electrons with heavy hydrogen-like ions is studied. Calculations are performed for the recombination into the 21S0 state of helium-like thorium and gadolinium, where, due to the near-degeneracy of the opposite-parity 21S0 and 23P0 states, the effect is strongly enhanced. Two scenarios for possible experiments are studied. In the first scenario, the electron beam is assumed to be fully polarized while the H-like ions are unpolarized, and the polarization of the emitted photons is not detected. In the second scenario, the linearly polarized photons are detected in an experiment with unpolarized electrons and ions. Corresponding calculations for the recombination into the 23P0 state are presented as well.

The elastic scattering of twisted electrons by diatomic molecules is studied within the framework of the non-relativistic first Born approximation. In this process, the coherent interaction of incident electrons with two molecular centers may cause interference patterns in the angular distributions of outgoing particles. We investigate how this Young-type interference is influenced by the complex internal structure of twisted beams. In particular, we show that the corkscrew-like phase front and the inhomogeneous intensity profile of the incident beam can strongly modify the angular distribution of electrons, scattered off a single well-localized molecule. For the collision with a macroscopic target, composed of randomly distributed but aligned molecules, the angular-differential cross section may reveal valuable information about the transverse and longitudinal momenta of twisted states. In order to illustrate the difference between the scattering of twisted and plane-wave beams for both, single-molecule and macroscopic-target scenarios, detailed calculations have been performed for a H2 target.

Collisions of antiprotons with He-, Ne-, Ni-like, bare, and neutral uranium are studied theoretically for scattering angles close to 180 • and antiproton energies with the interval 100 eV -10 keV.We investigate the Coulomb glory effect which is caused by a screening of the Coulomb potential of the nucleus and results in a prominent maximum of the differential cross section in the backward direction at some energies of the incident particle. We found that for larger numbers of electrons in the ion the effect becomes more pronounced and shifts to higher energies of the antiproton. On the other hand, a maximum of the differential cross section in the backward direction can also be found in the scattering of antiprotons on a bare uranium nucleus. The latter case can be regarded as a manifestation of the screening property of the vacuum-polarization potential in non-relativistic collisions of heavy particles.

Collisions of antiprotons with bare uranium nuclei are studied for scattering angles nearby 180 • in the framework of relativistic theory. The Coulomb glory phenomenon is investigated at energies of the antiprotons in the range 100 eV to 2.5 keV. The vacuum polarization effect and the anomalous magnetic moment of the antiproton are taken into account. The estimations of possible influence of such effects as radiative recombination and antiproton annihilation are given.