Electrostatic potential of a slowly moving ion in quantum plasmas is studied. This potential is composed of the Debye-Hückel potential and the wake potential. The near-field-wake potential is found. The binding energy levels of one-electron bound states of the ion are calculated by use of the Ritz variation method. The trial wave function contains three variational parameters. The presence of the wake field splits the binding energy levels. This effect is analogous to the Zeeman effect. The removal of the degeneracy of binding energy levels is influenced by the speed of ion and the number density of electrons. Compared with binding energy levels of a free ion, some binding energy levels of a moving ion in quantum plasmas are "pushed up."

Numerical comparisons of five screened potentials of dense plasma, namely, ion-sphere, Thomas-Fermi, generalized exponential-cosine, Shukla-Eliasson (SE), and Akbari-Moghanjoughi (AM), are conducted. Bound energy levels of ions in quantum plasma are calculated using the five screened potentials. Our results show that AM and SE models are different from the other three models.

The degree of linear polarization and angular distribution of the x-ray photoemission of highly charged He-like and Li-like uranium ions following electron-impact excitation and dielectronic recombination processes are calculated using a fully relativistic distorted-wave method. A detailed investigation is carried out regarding the contribution of the magnetic quadropole (M2) term to the subsequent characteristic x-ray emission from the above two different processes. It is found that while the M2 term has a slight effect on the angular distribution and linear polarization of electron-impact excitation, it has a substantial effect on the same properties of dielectronic recombination.

The studies of the influence of plasma environments on the level structures and transition properties for highly charged ions are presented. For the relativistic treatment, we implemented the multiconfiguration Dirac-Fock method incorporating the ion sphere (IS) model potential, in which the plasma screening is taken into account as a modified interaction potential between the electron and the nucleus. For the nonrelativistic treatment, analytical solutions of the Schrödinger equation with two types of the IS screened potential are proposed. The Ritz variation method is used with hydrogenic wave function as a trial wave function that contains two unknown variational parameters. Bound energies are derived from an energy equation, and the variational parameters are obtained from the minimisation condition of the expectation value of the energy. Numerical results for hydrogen-like ions in dense plasmas are presented as examples. A detailed analysis of the influence of relativistic effects on the energy levels and transition properties is also reported. Our results are compared with available results in the literature showing a good quantitative agreement.

Systematic investigations are performed for the energy levels and radiative properties for selected He-like C4+, Ne8+, Ar16+, and Kr34+ ions embedded in weakly coupled plasmas. For the conditions in which the Coulomb coupling parameter is small, the standard Debye model is adopted to describe the plasma screening effects. Within the relativistic framework, the modified version of the Flexible Atomic Code computations is carried out by considering a Debye-Hückel potential, in which the plasma screening is taken into account for both the electron-nucleus and electron-electron (e-e) interactions. An independent calculation for various Debye lengths is also presented using the multiconfiguration Dirac-Fock method for comparison purposes. For the nonrelativistic treatment, the analytical solution of the Schrödinger equation with the Debye screened potential is proposed. The variation method is developed with Slater wave function as a trial wave function that contains the variational parameters. An exact analytical expression of relativistic corrections such as the mass-velocity correction, the one/two-body Darwin correction, the spin-spin contact interaction correction, and the orbit-orbit interaction correction is derived. Differences among our three kinds of calculated energy levels and transition properties are analyzed in terms of the nuclear charge and/or the Debye length. Systematic trend is observed for all the properties under study with respect to increased screening. The influence of relativistic effects is also investigated in detail and found to play an important role in these systems. Our results are compared with available results from other theoretical calculations and the experimental values in the literature, and a good agreement is achieved. This work should be useful for astrophysical applications where such plasma environments exist.