The Atomic Structure Of Superheavy Element Uus(Z=117) And Its Stability Of Different Ionized Stages In Acid Solutions

During the past decades, the synthesis of the superheavy elements (SHE) has made significant progress. With the collaboration of Russian and American scientists, the dis-covery of two isotopes 293Uuså'Œ294Uus of element Uus (Z=117) was announced by the Joint Institute for Nuclear Research in Dubna. The synthesis of Uus fills the gap on the periodic table up to element 118 and offers more details to study the heaviest known "is-land of stability". In this thesis, we systematically study the atomic (ionic) structure and transition properties of element Uus by using the Grasp2K package based on the multi-configuration Dirac-Fock theory. Furthermore, we employ the accurate atomic structure parameters obtained from the MCDF calculations to estimate the standard electrode po-tentials of element Uus based on the Born-Haber thermodynamic cycle. Then we predict some chemical behavior of element Uus in acid solutions. The main work is divided into two parts:1). Systematic study of atomic (ionic) energy levels and excitation and ionic state properties. We calculated the first five ionization potentials, electron affinities, resonance excitation energies, oscillator strengths, and radii for the element Uus and its homologue At. Main valence correlation effects were taken into account and the Breit interaction and QED effects were also estimated. The present results can be used for the predictions of some important physicochemical properties of element Uus. We also predict a strong line which is suitable for observing low-lying level structure for element Uus.2). Prediction of the stability of different ionized Uus in acid solutions by calculating its standard electrode potentials. Based on the theory of Born-Haber thermodynamic cycle, the standard electrode potentials for superheavy element Uus (Z=II7), in acid solutions have been estimated by using the linear correlation between the available ex-perimental potential values and electron affinities and ionization potentials of concerned elements calculated from the multiconfiguration Dirac-Fock (MCDF) method. The results indicate that the 0 and 1+ states of Uus can stably exist in the acid solutions while the 1-and 5+ states can not. The stability of these states follows the trend of periodical tables, apart from the 5+ state. These results have been explained from the relative positions of the energy levels of the valence electrons and the ionization process.In summary, We provide the accurate atomic structural parameters of superheavy element Uus (Z=117) and its element diagram. On the basis of this, we predict the stability of different ionized Uus in acid solutions. We hope this research can provide theoretical support to available spectra measurement of Uus, and can be helpful for the understanding of the chemical behavior of element Uus in acid solutions and can assist possible experimental study in the future.