Experimental rate coefficients of F⁵⁺ recombining into F⁴⁺

¹ Department of PhysicsStockholm University, AlbaNova 10691 Stockholm, Sweden
e-mail: safdaruetian@gmail.com
² Department of Physics, Auburn University, Auburn, AL 36849, USA
³ Department of Physics, University of Gujrat, 50700 Gujrat, Pakistan

Received: 25 October 2012
Accepted: 19 May 2013

Abstract

Recombination spectra of F⁵⁺ producing F⁴⁺ have been investigated with high-energy resolution, using the CRYRING heavy-ion storage ring. The absolute recombination rate coefficients are derived in the centre-of-mass energy range of 0−25 eV. The experimental results are compared with intermediate-coupling AUTOSTRUCTURE calculations for 2s−2p (△n = 0) core excitation and show very good agreement in the resonance energy positions and intensities. Trielectronic recombination with 2s²−2p² transitions are clearly identified in the spectrum. Contributions from F⁵⁺ ions in an initial metastable state are also considered. The energy-dependent recombination spectra are convoluted with Maxwell-Boltzmann energy distribution in the 10³−10⁶ K temperature range. The resulting temperature-dependent rate coefficients are compared with theoretical results from the literature. In the 10³−10⁴ K range, the calculated data significantly underestimates the plasma recombination rate coefficients. Above 8 × 10⁴ K, our AUTOSTRUCTURE results and plasma rate coefficients from elsewhere show agreement that is better than 25% with the experimental results.