Plasma screening effects on the electronic structure of multiply charged Al ions using Debye and ion-sphere models

We analyze atomic structures of plasma-embedded aluminum (Al) atom and its ions in the weak- and strong-coupling regimes. The plasma screening effects in these atomic systems are accounted for using the Debye and ion-sphere (IS) potentials for the weakly and strongly coupled plasmas, respectively. Within the Debye model, special attention is given to investigate the spherical and nonspherical plasma screening effects considering in the electron-electron interaction potential. The relativistic coupled-cluster (RCC) method has been employed to describe the relativistic and electronic correlation effects in the above atomic systems. The variations in the ionization potentials (IPs) and excitation energies (EEs) of the plasma-embedded Al ions are presented. It is found that the atomic systems exhibit more stability when the exact screening effects are taken into account. It is also shown that in the presence of a strongly coupled plasma environment, the highly ionized Al ions show blueshifts and redshifts in the spectral lines of the transitions between the states with the same and different principal quantum numbers, respectively. Comparison among the results obtained from the Debye and IS models are also carried out considering similar plasma conditions.

Figure 1

Variation in the ionization potentials (IPs) with the Debye screening length in (a) Al i, (b) Al iii, (c) Al ix, and (d) Al xi.

Figure 2

Variation in the first EE (in ${\mathrm{cm}}^{-1}$) of (i) Al i, (ii) Al iii, (iii) Al ix, and (iv) Al xi with the Debye screening length $D$ (in a.u.).

Figure 3

Variation of ionization potential (IP) in the Al iii ion with the ion-sphere radius $R$ (in a.u.). Inset plots are shown for the Al ix and Al xi ions.

Figure 4

Variation of EE of the $3P_{1/2}$ state in the Al iii ion with the IS radius $R$ (a.u.).

Figure 5

Variation of EE of the $3S_{1/2}$ state in the Al ix ion with the IS radius $R$ (a.u.).

Figure 6

Variation of EE of the $2P_{1/2}$ state in the Al xi ion with IS radius $R$ (a.u.).