Eur. Phys. J. D (2012) 66: 125
https://doi.org/10.1140/epjd/e2012-20594-6

Regular Article

Energy levels and multipole transition properties of C⁴⁺ ion in Debye plasmas

¹ The Key Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, P.O. Box 8009-26, Beijing 100088, P.R. China
² Key Laboratory of Atomic and Molecular Physics & Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, P.R. China
³ Macedonian Academy of Sciences and Arts, P.O. Box 428, 1000 Skopje, Macedonia
⁴ College of Physical Sciences, Graduate School of the Chinese Academy of Sciences, P.O. Box 4588, Beijing 100049, P.R. China

^a e-mail: xiely@nwnu.edu.cn

Received: 13 October 2011
Received in final form: 24 February 2012
Published online: 17 May 2012

Abstract

Plasma screening effects on the energy structure and radiative transition properties of helium-like C⁴⁺ ions embedded in Debye plasmas are investigated by using the multi-configuration Dirac-Hartree-Fock method incorporating the Debye-Hückel potential for both the electron-nucleus and electron-electron interactions. Seventeen fine-structure energy levels of the low-lying 1s², 1s2l(l = s,p) and 1s3l′(l′ = s,p,d) configurations, as well as the electric-dipole (E1), magnetic-dipole (M1) and magnetic-quadrupole (M2) transition probabilities and oscillator strengths between these levels have been calculated over a wide range of screening parameters. It is found that the plasma screening leads to a decrease of excitation energies and alters the energy levels remarkably. For Δn ≠ 0 transitions, the spontaneous decay spectra are red-shifted and their oscillator strengths and transition probabilities decrease with increasing the interaction screening, while those for the Δn = 0 transitions exhibit opposite patterns. The influence of electron-nucleus and electron-electron screened interactions on the changes of energy levels and transition properties are analyzed. Comparison is made of present results with other data available in the literature for this ion.