Influence of dense quantum plasmas on fine-structure splitting of Lyman doublets of hydrogenic systems

Relativistic calculations are performed to study the effects of oscillatory quantum plasma screening on the fine-structure splitting between the components of Lyman-alpha and beta line doublets of atomic hydrogen and hydrgen-like argon ion within dense quantum plasmas, where the effective two-body (electron-nucleus) interaction is modeled by the Shukla-Eliasson oscillatory exponential cosine screened-Coulomb potential. The numerical solutions of the radial Dirac equation for the quantum plasma-embedded atomic systems reveal that the oscillatory quantum screening effect suppresses the doublet (energy) splitting substantially and the suppression becomes more prominent at large quantum wave number k(q). In the absence of the oscillatory cosine screening term, much larger amount of suppression is noticed at larger values of k(q), and the corresponding results represent the screening effect of an exponential screened-Coulomb two-body interaction. The Z(4) scaling of the Lyman doublet splitting in low-Z hydrogen isoelectronic series of ions in free space is violated in dense quantum plasma environments. The relativistic data for the doublet splitting in the zero screening (k(q) = 0) case are in very good agreement with the NIST reference data, with slight discrepancies (similar to 0.2%) arising from the neglect of the quantum electrodynamic effects. (C) 2015 AIP Publishing LLC.