Spectral properties of helium‐like ions under strongly coupled plasma conditions

Abstract

Systematic investigations have been performed to study the effect of strongly coupled plasma on the dynamic polarizabilities, low-lying energy levels, oscillator strengths, and transition probabilities for the helium isoelectronic ions . An ion-sphere (IS) model of the plasma has been adopted and time-dependent perturbation theory has been applied to calculate the energy levels and other transition properties. Systematic trend is observed for the spectroscopic properties along the isoelectronic sequence under a given plasma strength and also for a given ion under different plasma strengths. The ionization potential for a given ion is found to decrease, and the number of bound excited states has become finite under increased plasma strengths. The spectral line shifts under such plasma environment have been calculated.

The influence of Debye plasma on the ground state energies of exotic systems

“…For this purpose we computed the dipole polarizabilities of the two-particle systems, using the standard linear response theory with a perturbed function chosen as linear combination of eight STO's [12]. The quality of results is again checked against the standard second order perturbation theory results for the plasma-free hydrogen-like systems (see Tables 1-3).…”

“…constructed of Slater type orbitals are to take care of the radial correlation whereas η j (1, 2) ∼ r n j 12 e −β j r 12 describe the angular proton-proton (d-d or t-t) correlations dependent on the distance between them, r 12 . In actual computations we used eight different exponent parameters ρ which resulted in 36 different χ kl functions.…”

“…Study of the effect of external environment like that of a plasma on the energy levels and other structural properties of atomic, ionic and exotic systems has become a subject of extensive investigations in recent years [1][2][3][4][5][6][7][8][9][10][11][12]. A broad discussion on the subject matter was given by Griem [13], Fujimoto [14], Ichimaru [15] and Rajagopal [16].…”

Effect of strongly coupled plasma on the spectra of hydrogenlike carbon, aluminium and argon

“…In addition to evaluation of the ground state energies at different plasma coupling strengths we apply an external time dependent perturbation [21][22][23][24] for probing the low lying excited states of the system. The transition energies and excited state wave functions have been calculated using linear response theory under such a perturbation [21][22][23][24]. The procedure yields the spectral line positions and other excitation properties under the plasma environment.…”

“…In addition we would also like to investigate the applicability of the Debye plasma model with a spherical confinement on the spectral line positions and shifts of the Lyman lines under the laser plasma experimental The European Physical Journal D conditions [10][11][12] and to estimate the shifts in ionization potentials. Such studies have been done earlier for hydrogen [21,22] and helium like systems [23,24] to understand the behavior of the structural properties of one and two electron systems under weak as well as strongly coupled plasmas. A brief outline of the theory is given in Section 2 and a discussion of the results follow in Section 3.…”