Dielectronic Recombination of FexxiiiForming Fexxii: Laboratory Measurements and Theoretical Calculations

Abstract

We have measured resonance strengths and energies for dielectronic recombination (DR) of beryllium-like Fe xxiii forming boron-like Fe xxii via N ¼ 2 ! N 0 ¼ 2 and N ¼ 2 ! N 0 ¼ 3 core excitations. All measurements were carried out using the heavy-ion Test Storage Ring at the Max Planck Institute for Nuclear Physics (MPI-K) in Heidelberg, Germany. We have also calculated these resonance strengths and energies using three independent, perturbative, state-of-the-art theoretical techniques: the multiconfiguration Breit-Pauli (MCBP) method, the multiconfiguration Dirac-Fock (MCDF ) method, and the Flexible Atomic Code (FAC). Overall reasonable agreement is found between our experimental results and these theoretical calculations. We have used our measurements to produce a Maxwellian-averaged DR rate coefficient for Fe xxiii. Our experimentally derived rate coefficient is estimated to be accurate to better that %20%. At temperatures where Fe xxiii is predicted to form in both photoionized and electron-ionized gas, we find mixed agreement between our experimental rate coefficient and previously published rate coefficients. We find good agreement at these temperatures between the experimentally derived rate coefficient and our MCBP, MCDF, and FAC results.

Storage-Ring Measurement of the Hyperfine InducedTi18+47(2s2p P0Schippers1, Ew2, Bernhardt3 et al. 2007Phys. Rev. Lett.Self Cite802611View full textAdd to dashboardCite

“…The autostructure calculations of the recombination spectrum indicate an average population of ∼5% for the metastable Ti 18+ (2s2p 3 P 0 ) ions in the stored 48 Ti 18+ beam. A similar average population of the 2s2p 3 P 0 metastable state was found in a recent DR experiment with Be-like 56 Fe 22+ [24]. For the determination of the time constant associated with the hyperfine quenching the decay of the 47 Ti 18+ ( 3 P 0 ) beam component was monitored as a function of storage time.…”

Photorecombination of berylliumlike Ti18+: Hyperfine quenching of dielectronic resonances

“…The energy range 0-80 eV comprises all resonances associated with 2s → 2p (∆N = 0) core excitations. The spectrum is similar to the previously measured ones of the isoelectronic ions Cl 13+ [14] and Fe 22+ [15]. At higher energies it is dominated by the regular Rydberg series of 2s 2 1 S 0 → (2s 2p 1 P 1 ) nℓ DR resonances converging to the 2s 2p 1 P 1 series limit at 73.11 eV [13].…”

Recombination rate coefficients of Be-like neon

“…Later, Schippers et al (2004) investigated the recombination spectrum of Be-like Mg. For this ion distinct contribution from TR in the form of several sharp peaks was also found. Toward higher Z ions, some TR resonance features appear in the recombination spectrum of Ti 18+ (Schippers et al 2007) whereas in case of Fe 22+ only one clear peak could be attributed to TR (Savin et al 2006). Important TR contributions were observed by Fogle et al (2005), in the spectra of Be-like N and Be-like O, whereas in the spectrum of Be-like C, TR did not have a notable contribution.…”