Updating of atomic data needed for ionization balance evaluations of krypton and molybdenum

Mattioli, M.; Mazzitelli, G.; Fournier, K. B.; Finkenthal, M.; Carraro, L.

doi:10.1088/0953-4075/39/21/010

Cited by 19 publications

(19 citation statements)

References 92 publications

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“…Equations (1) and (2) can be used to fit the lowtemperature behavior of the RR rate coefficients, but a different (dotted curve), Kr 3+ (short-dashed curve), Kr 4+ (dash-dot-dash curve), Kr 5+ (long-dashed curve), and Kr 6+ (dash-dot-dot-dot-dash curve). For comparison, the approximate rate coefficients of Mattioli et al (2006) are depicted as gray curves, with the line styles corresponding to the same ions.…”

Section: Radiative Recombination Rate Coefficientsmentioning

confidence: 99%

“…6. For comparison, we plot the approximate RR rate coefficients of Mattioli et al (2006) as gray curves. It can be seen that the Mattioli et al (2006) rate coefficients are at least three orders of magnitude too small over the full range of temperatures.…”

Section: Radiative Recombination Rate Coefficientsmentioning

confidence: 99%

“…For comparison, we plot the approximate RR rate coefficients of Mattioli et al (2006) as gray curves. It can be seen that the Mattioli et al (2006) rate coefficients are at least three orders of magnitude too small over the full range of temperatures. As stated in their paper, their RR rate coefficients are rough estimates, with valence shell states treated separately from excited shells (which were taken to be hydrogenic).…”

Section: Radiative Recombination Rate Coefficientsmentioning

confidence: 99%

“…The rate coefficients for different ions are wildly dissimilar at low temperatures due to differences in the structure of near-threshold autoionizing resonances, but show similar behavior at high temperatures. Mattioli et al (2006) also computed DR rate coefficients for low-charge Kr ions (shown in Fig. 7 as gray curves), in order to properly model its cooling rate coefficient in magneticallyconfined fusion plasmas.…”

Section: Dielectronic Recombination Rate Coefficientsmentioning

confidence: 99%

“…Mattioli et al (2006) compiled RR and DR rate coefficients for all Kr ions, but the data for lowcharge ions are rough estimates. For these species, DR rate coefficients were computed using the Burgess formula (Burgess 1965), as modified by Merts et al (1976), which is appropriate for collisionally-ionized plasmas (indeed, the work of Mattioli et al was inspired by the utility of Kr as a coolant for magnetically-confined fusion plasmas), but is known to badly underestimate the rate coefficient at the low temperatures of photoionized plasmas.…”

Section: Introductionmentioning

confidence: 99%

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Atomic data for neutron-capture elements

Sterling

Witthoeft

2011

A&A

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We present multi-configuration Breit-Pauli distorted-wave photoionization (PI) cross sections and radiative recombination (RR) and dielectronic recombination (DR) rate coefficients for the first six krypton ions. These were calculated with the AUTOSTRUCTURE code, using semi-relativistic radial wavefunctions in intermediate coupling. Kr has been detected in several planetary nebulae (PNe) and H II regions, and is a useful tracer of neutron-capture nucleosynthesis. PI, RR, and DR data are required to accurately correct for unobserved Kr ions in photoionized nebulae, and hence to determine elemental Kr abundances. PI cross sections have been determined for ground configuration states of Kr 0 −Kr 5+ up to 100 Rydbergs. Our Kr + PI calculations were significantly improved through comparison with experimental measurements. RR and DR rate coefficients were respectively determined from the direct and resonant PI cross sections at temperatures (10 1 −10 7 )z 2 K, where z is the charge. We account for Δn = 0 DR core excitations, and find that DR is the dominant recombination mechanism for all but Kr + at photoionized plasma temperatures. Internal uncertainties are estimated by comparing results computed with three different configuration-interaction expansions for each ion, and by testing the sensitivity to variations in the orbital radial scaling parameters. The PI cross sections are generally uncertain by 30−50% near the ground state thresholds. Near 10 4 K, the RR rate coefficients are typically uncertain by less than 10%, while those of DR exhibit uncertainties of factors of 2 to 3, due to the unknown energies of near-threshold autoionizing resonances. With the charge transfer rate coefficients presented in the third paper of this series, these data enable robust Kr abundance determinations in photoionized nebulae for the first time, providing a new tool for studying heavy element enrichments in PNe and for investigating the chemical evolution of trans-iron elements.

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Section: Radiative Recombination Rate Coefficientsmentioning

confidence: 99%

Section: Radiative Recombination Rate Coefficientsmentioning

confidence: 99%

Section: Radiative Recombination Rate Coefficientsmentioning

confidence: 99%

Section: Dielectronic Recombination Rate Coefficientsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Atomic data for neutron-capture elements

Sterling

Witthoeft

2011

A&A

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Energy levels, transition rates and electron impact excitation rates for B-like Kr XXXII

et al. 2020

Atomic Data and Nuclear Data Tables

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Energy levels and transition rates for electric-dipole, electric-quadrupole, electric-octupole, magnetic-dipole, and magneticquadrupole transitions among the levels arising from the n ≤ 5 configurations in B-like Kr XXXII are calculated by using two state-of-the-art methods, namely, the multi-configuration Dirac-Hartree-Fock (MCDHF) approach and the second-order many-body perturbation theory (RMBPT). Our results are compared with several available experimental and other theoretical values. Electron-impact excitation (EIE) collision strengths are calculated via the independent process and isolated resonance approximation using distorted-wave (denoted by IPIRDW). Radiation damping effects on the resonance excitation contributions are included. Effective collision strengths are calculated as a function of electron temperature by assuming a Maxwellian electron velocity distribution. Spectral line intensities are modeled by using collision radiative model, and several line pairs pointed out might be useful for density diagnostics.It is well known that atomic spectroscopy of highly-charged ions is of particular interest for plasma control and plasma diagnostics on chemical composition, electron density and temperature, and electric and magnetic fields. Krypton, as a rare gas, has been widely used in diagnosing tokamak fusion plasmas [1-3], since it does not pollute the vacuum vessel and is easily introduced into the plasmas. Furthermore, due to its almost ideal ionization balance and ease of injection, krypton has been the prime candidate for core Doppler spectroscopy on ITER [4][5][6]. Atomic data (including energy levels, transition rates, collision strengths, etc.) are required for many krypton ions. Recently, we reported accurate level energies, transition parameters and lifetimes for Kr XXIV [7], Kr XXV [8] and Kr XXVII -Kr XXXI [9-13], using both the RMBPT approach and MCDHF method. This work reports our efforts for B-like Kr XXXII.The experimental studies on B-like Kr were very limited [1,2,[14][15][16][17], and only 11 n = 2 levels have been compiled by the Atomic Spectra Database (ASD) of the National Institute of Standards and Technology (NIST) [18]. Most of the existing theoretical calculations were confined to the n = 2 and n = 3 configurations [19-28]. Of particular note was the work presented by Aggarwal et al. [26], in which the Flexible Atomic Code (FAC) [29] and GRASP0 package [30] have been adopted to obtain level energies, lifetimes, wavelengths and transition rates for transitions among the lowest 125 levels of the n ≤ 3 configurations. In addition, Aggarwal et al. [31] also adopted the fully relativistic Dirac Atomic R-matrix Code (DARC) of Norrington and Grant to calculate collision strengths and effective collision strengths. Recently, Liang et al. [32] adopted Thomas-Femi-Dirac-Amaldi model potential from AUTOSTRUCTURE (AS) [33] to calculate the energy levels, line strengths and lifetimes for the 204 n ≤ 4 energy levels of several B-like ions including Kr XXXII. Meanwhile, Liang et al. [32] perf...

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