High Rydberg resonances in dielectronic recombination of pb(79+)

Area of Science:

• Atomic Physics
• Atomic Spectroscopy
• Quantum Electrodynamics

Background:

• Dielectronic recombination (DR) is a key process in highly charged ions, influencing plasma properties.
• Understanding DR is crucial for astrophysical and laboratory plasmas.
• Previous studies often neglected high-angular-momentum contributions in DR calculations.

Purpose of the Study:

• To experimentally measure dielectronic recombination resonances in lead ions (Pb 79+).
• To investigate the contribution of high-angular-momentum states to DR resonance strength.
• To compare experimental findings with relativistic theoretical predictions.

Main Methods:

• Experiments were conducted at the Experimental Storage Ring (ESR) at GSI.
• Dielectronic recombination resonances associated with 2s(1/2)-->2p(1/2) excitations were measured.
• Absolute rate coefficients were determined, and the fine structure of resonance manifolds was analyzed.

Main Results:

• The fine structure of the lowest resonance manifold (Pb 78+) was partially resolved around 18 eV.
• Absolute rate coefficients for dielectronic recombination were obtained.
• Experimental data confirmed significant contributions from high-angular-momentum components (up to j=31/2).

Conclusions:

• The study demonstrates the significant role of high-angular-momentum states in dielectronic recombination for highly charged ions.
• The findings necessitate a revision of the assumption that high-angular-momentum contributions are negligible.
• Accurate theoretical models for highly charged ions must include these contributions for precise predictions.