Recombination rate coefficients of Be-like neon

Orbán, Istvan; Böhm, Sebastian; Loch, S. D.; Schuch, R.

doi:10.1051/0004-6361:200810295

Cited by 16 publications

(9 citation statements)

References 32 publications

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“…The scaling factor is 0.83, which suggests that 17% ions are in the metastable state. This estimated metastable fraction is supported by other experiments at CRYRING, such as 14% 3 P 0 metastable fraction of Ne 6+ ions (Orban et al 2008) and 15% 2 P 3/2 fraction of F 5+ ions .…”

Section: Merged-beam Recombination Rate Coefficientssupporting

confidence: 82%

“…Electron-ion recombination of Ne ions, for example, Ne 6+ (Orban et al 2008), Ne 7+ (Zong et al 1998;Böhm et al 2001Böhm et al , 2005, and Ne 10+ (Gao et al 1995(Gao et al , 1997, have been studied in storage ring experiments so far. In this paper, we report the first measurement of the recombination rate coefficient for the Ne 5+ recombining into Ne 4+ .…”

Section: Introductionmentioning

confidence: 99%

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RECOMBINATION RATE COEFFICIENTS OF BORON-LIKE Ne

Mahmood

Orbán

Ali

et al. 2013

ApJ

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Recombination of Ne 5+ was measured in a merged-beam type experiment at the heavy-ion storage ring CRYRING. In the collision energy range 0-110 eV resonances due to 2s 2 2p → 2s2p 2 (Δn = 0) and 2s 2 2p → 2s 2 3l (Δn = 1), core excitations were observed. The experimentally derived rate coefficients agree well with the calculations obtained using AUTOSTRUCTURE. At low energies, recombination is dominated by resonances belonging to the spinforbidden 2s2p 2 ( 4 P J )nl series. The energy-dependent rate coefficients were convoluted with a Maxwell-Boltzmann electron energy distribution to obtain plasma recombination rate coefficients. The data from the literature deviate from the measured results at low temperature.

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Section: Merged-beam Recombination Rate Coefficientssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

RECOMBINATION RATE COEFFICIENTS OF BORON-LIKE Ne

Mahmood

Orbán

Ali

et al. 2013

ApJ

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“…Some experiments estimate the metastable fraction by comparing the measured and calculated DR resonance cusp at the ΔN = 0 series limit and scale up the measured data to match theory there. This procedure may erroneously eliminate any signature of the high-n discrepancy (e.g., Fogle et al 2005;Orban et al 2008Orban et al , 2010. For some Be-like systems, the metastable compositions were determined by other means with uncertainties commonly well below the typical uncertainties of ∼25% for DR MBRRC at a 90% confidence level.…”

Section: Discussion Of High-n Dr Via δN = 0 Core Excitationsmentioning

confidence: 99%

ELECTRON-ION RECOMBINATION OF Mg^{6 +}FORMING Mg^{5 +}AND OF Mg^{7 +}FORMING Mg^{6 +}: LABORATORY MEASUREMENTS AND THEORETICAL CALCULATIONS

Lestinsky

Badnell

Bernhardt

et al. 2012

ApJ

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We have measured electron-ion recombination for C-like Mg 6+ forming Mg 5+ , and for B-like Mg 7+ forming Mg 6+ . These studies were performed using a merged electron-ion beam arrangement at the TSR heavy ion storage ring located in Heidelberg, Germany. Both primary ions have metastable levels with significant lifetimes. Using a simple cascade model we estimate the population fractions in these metastable levels. For the Mg 6+ results, we find that the majority of the stored ions are in a metastable level, while for Mg 7+ the metastable fraction is insignificant. We present the Mg 6+ merged beams recombination rate coefficient for DR via N = 2 → N = 2 core electron excitations (ΔN = 0 DR) and for Mg 7+ via 2 → 2 and 2 → 3 core excitations. Taking the estimated metastable populations into account, we compare our results to state-of-the-art multiconfiguration Breit-Pauli theoretical calculations. Significant differences are found at low energies where theory is known to be unreliable. Moreover, for both ions we observe a discrepancy between experiment and theory for ΔN = 0 DR involving capture into high-n Rydberg levels and where the stabilization is primarily due to a radiative transition of the excited core electron. This is consistent with previous DR experiments on M-shell iron ions which were performed at TSR. The large metastable content of the Mg 6+ ion beam precludes generating a plasma recombination rate coefficient (PRRC). However, this is not an issue for Mg 7+ and we present an experimentally derived Mg 7+ PRRC for plasma temperatures from 400 K to 10 7 K with an estimated uncertainty of less than 27% at a 90% confidence level. We also provide a fit to our experimentally derived PRRC for use in plasma modeling codes.

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“…It is noted that the significance of TR was first discovered for Be-like Cl 13+ [24] and subsequently confirmed for other ions from this isoelectronic sequence [19][20][21][22]. The boron isoelectronic sequence has been less intensely studied.…”

Section: +mentioning

confidence: 98%

Absolute rate coefficients for photorecombination of beryllium-like and boron-like silicon ions

Bernhardt

Becker

Brandau

et al. 2016

J. Phys. B: At. Mol. Opt. Phys.

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Abstract. We report measured rate coefficients for electron-ion recombination for Si 10+ forming Si 9+ and for Si 9+ forming Si 8+ , respectively. The measurements were performed using the electron-ion merged-beams technique at a heavy-ion storage ring. Electron-ion collision energies ranged from 0 to 50 eV for Si 9+ and from 0 to 2000 eV for Si 10+ , thus, extending previous measurements for Si 10+ [Orban et al 2010 Astrophys. J. 721 1603] to much higher energies. Experimentally derived rate coefficients for the recombination of Si 9+ and Si 10+ ions in a plasma are presented along with simple parameterizations. These rate coefficients are useful for the modeling of the charge balance of silicon in photoionized plasmas (Si 9+ and Si 10+ ) and in collisionally ionized plasmas (Si 10+ only). In the corresponding temperature ranges, the experimentally derived rate coefficients agree with the latest corresponding theoretical results within the experimental uncertainties.

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Recombination rate coefficients of Be-like neon

Cited by 16 publications

References 32 publications

RECOMBINATION RATE COEFFICIENTS OF BORON-LIKE Ne

RECOMBINATION RATE COEFFICIENTS OF BORON-LIKE Ne

ELECTRON-ION RECOMBINATION OF Mg^{6 +}FORMING Mg^{5 +}AND OF Mg^{7 +}FORMING Mg^{6 +}: LABORATORY MEASUREMENTS AND THEORETICAL CALCULATIONS

Absolute rate coefficients for photorecombination of beryllium-like and boron-like silicon ions

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Recombination rate coefficients of Be-like neon

Cited by 16 publications

References 32 publications

RECOMBINATION RATE COEFFICIENTS OF BORON-LIKE Ne

RECOMBINATION RATE COEFFICIENTS OF BORON-LIKE Ne

ELECTRON-ION RECOMBINATION OF Mg6 +FORMING Mg5 +AND OF Mg7 +FORMING Mg6 +: LABORATORY MEASUREMENTS AND THEORETICAL CALCULATIONS

Absolute rate coefficients for photorecombination of beryllium-like and boron-like silicon ions

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ELECTRON-ION RECOMBINATION OF Mg^{6 +}FORMING Mg^{5 +}AND OF Mg^{7 +}FORMING Mg^{6 +}: LABORATORY MEASUREMENTS AND THEORETICAL CALCULATIONS