- ID:
- ivo://CDS.VizieR/J/A+A/427/763
- Title:
- FeX E1, E2, M1 and M2 transitions
- Short Name:
- J/A+A/427/763
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Energies of the 54 levels belonging to the (1s^2^2s^2^2p^6^) 3s^2^3p^5^, 3s3p^6^, 3s^2^3p^4^3d and 3s3p^5^3d configurations of FeX have been calculated using the GRASP code of Dyall et al. (1989, Comput. Phys. Commun, 55, 424). Additionally, radiative rates, oscillator strengths, and line strengths are calculated for all electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), and magnetic quadrupole (M2) transitions among these levels. Comparisons are made with results available in the literature, and the accuracy of the data is assessed. Our energy levels are estimated to be accurate to better than 3%, whereas results for other parameters are probably accurate to better than 20%. Additionally, the agreement between measured and calculated lifetimes is better than 10%.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/414/377
- Title:
- FeX-FeXVII fine-structure K-vacancy levels
- Short Name:
- J/A+A/414/377
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report extensive calculations of the decay properties of fine-structure K-vacancy levels in Fe X-Fe XVII. A large set of level energies, wavelengths, radiative and Auger rates, and fluorescence yields has been computed using three different standard atomic codes, namely Cowan's HFR, AUTOSTRUCTURE and the Breit-Pauli R-matrix package. This multi-code approach is used to the study the effects of core relaxation, configuration interaction and the Breit interaction, and enables the estimate of statistical accuracy ratings. The K-alpha and KLL Auger widths have been found to be nearly independent of both the outer-electron configuration and electron occupancy keeping a constant ratio of 1.53+/-0.06. By comparing with previous theoretical and measured wavelengths, the accuracy of the present set is determined to be within 2m{AA}. Also, the good agreement found between the different radiative and Auger data sets that have been computed allow us to propose with confidence an accuracy rating of 20% for the line fluorescence yields greater than 0.01. Emission and absorption spectral features are predicted finding good correlation with measurements in both laboratory and astrophysical plasmas.
- ID:
- ivo://CDS.VizieR/J/A+A/433/731
- Title:
- Fe XII Benchmarking atomic data
- Short Name:
- J/A+A/433/731
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use recently calculated electron collisional data by Storey et al. (2005A&A...433..717S) for Fe XII (n=3 configurations) to build a model ion to compare to spectroscopic observations of the solar corona and laboratory measurements. We review all the line identifications of the brightest lines, by comparing both wavelengths and line intensities. The presence of blends in different plasma conditions is highlighted. A large number of new energy levels and line identifications are proposed. In particular, we identify the electric quadrupole ^4P_5/2_-^4^F_9/2_ transition with the bright coronal line observed at 592.6{AA}, previously unidentified. This line, when observed with the 1242.0, 1349.5 UV forbidden lines, is a good density diagnostic over a large range of electron densities. We also indicate the best spectral lines to be used for density diagnostics or instrument calibration. From various combinations of lines we obtain electron densities that are significantly different from those published in the previous literature. Some examples are provided. The agreement between theory and experimental data in terms of wavelengths, line intensities and level lifetimes is excellent.
- ID:
- ivo://CDS.VizieR/J/A+A/429/1117
- Title:
- Fe XIII effective collision strengths
- Short Name:
- J/A+A/429/1117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Effective collision strengths for transitions among the lowest 97 fine-structure levels belonging to the (1s^2^2s^2^2p^6^) 3s^2^3p^2^, 3s3p^3^, 3s^2^3p3d, 3p^4^, 3s3p^2^3d and 3s^2^3d^2^ configurations of Fe XIII have been calculated using the fully relativistic Dirac Atomic R-matrix Code (DARC) of Norrington & Grant (2004, Comput. Phys. Commun. - in prep.). Resonances have been resolved in the threshold region, and results are reported over a wide electron temperature range up to log T_e_=6.8K. Comparisons are made with the earlier available R-matrix results of Gupta & Tayal (1998ApJ...506..464G), and the accuracy of the data is assessed.
- ID:
- ivo://CDS.VizieR/J/A+A/511/A78
- Title:
- Fe XIII electron impact excitation
- Short Name:
- J/A+A/511/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new R-matrix calculation of rate coefficients for electron collisional excitation of Fe XIII is presented and compared to recent calculations of comparable complexity. At temperatures at which Fe^12+^ is typically found in the solar corona, the present results, which use the intermediate coupling frame transformation method, show significant differences compared to some earlier work. We use a large configuration interaction calculation with extensive correlation to assess the accuracy of our and earlier workers' scattering targets.
- ID:
- ivo://CDS.VizieR/J/A+A/543/A144
- Title:
- Fe XIII soft X-ray lines
- Short Name:
- J/A+A/543/A144
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new large-scale R-matrix (up to n=4) and distorted wave (up to n=6) scattering calculations for electron collisional excitation of Fe XIII. We aim to provide accurate atomic data for the soft X-rays, where strong n=4-n=3 transitions are present. As found in previous work on Fe X, resonances from within the n=4 levels and cascading from higher levels significantly increase the intensities of these lines. We provide a number of models and line intensities, and list a number of strong unidentified lines.
- ID:
- ivo://CDS.VizieR/J/A+A/543/A139
- Title:
- Fe XII soft X-ray lines
- Short Name:
- J/A+A/543/A139
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new large-scale R-matrix (up to n=4) and distorted-wave (DW, up to n=6) scattering calculations for electron collisional excitation of Fe XII. The first aim is to provide accurate atomic data for the soft X-rays, where strong decays from the n=4 levels are present. As found in previous work on Fe X, resonances attached to n=4 levels increase the cross-sections for excitations from the ground state to some n=4 levels, when compared to DW calculations. Cascading from higher levels is also important. We provide a number of models and line intensities, and list a number of strong unidentified lines. The second aim is to assess the effects of the large R-matrix calculation on the n=3 transitions. Compared to our previous (n=3) R-matrix calculation, we find overall excellent agreement to within a few percent, however a few key density diagnostic EUV intensities differ by about 60% at coronal densities. The new atomic data result in lower electron densities, resolving previous discrepancies with solar observations.
- ID:
- ivo://CDS.VizieR/J/A+A/370/1071
- Title:
- Fe XII UV line intensity ratios
- Short Name:
- J/A+A/370/1071
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new set of radiative and electron collisional data for Fe XII was presented in two earlier papers. In the present work, we derive level populations and theoretical line intensities for a range of plasma densities and temperatures. Observations of Fe XII lines obtained with the Solar EUV Rocket Telescope and Spectrograph are analysed both as a check on the quality of the new atomic data and to determine the electron density in active regions and the quiet Sun. The discrepancy between the electron density values determined from Fe XII line intensity ratios and those obtained from other ions is investigated.
- ID:
- ivo://CDS.VizieR/J/A+A/549/A42
- Title:
- FeXI soft X-ray lines
- Short Name:
- J/A+A/549/A42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new large-scale R-matrix (up to n=4) and distorted wave (up to n=6) scattering calculations for electron collisional excitation of Fe XI. These data are needed for the analysis of soft X-ray spectra of astrophysical plasmas, where strong n=4-->n=3 transitions are present. As found in previous work on Fe X, Fe XII, and Fe XIII, resonances from within the n=4 levels and cascading from higher levels significantly increase the intensities of these lines. We provide a list of the strongest lines, many of which are unidentified. The present larger model produces intensities for decays from n=3 levels mostly consistent with our previous work, however significant enhancements for some lower levels are found, in particular for the 3s^2^3p^3^3d^5^D which can be used to measure electron temperatures in the solar corona with the Hinode/EIS spectrometer.
- ID:
- ivo://CDS.VizieR/J/ApJ/767/123
- Title:
- FeXIV, FeXV and FeXVI transitions
- Short Name:
- J/ApJ/767/123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Fe unresolved transition arrays (UTAs) produce prominent features in the ~15-17{AA} wavelength range in the spectra of active galactic nuclei (AGNs). Here, we present new calculations of the energies and oscillator strengths of inner-shell lines from FeXIV, FeXV, and FeXVI. These are crucial ions since they are dominant at inflection points in the gas thermal stability curve, and UTA excitation followed by autoionization is an important ionization mechanism for these species. We incorporate these, and data reported in previous papers, into the plasma simulation code Cloudy. This updated physics is subsequently employed to reconsider the thermally stable phases in absorbing media in AGNs. We show how the absorption profile of the Fe XIV UTA depends on density, due to the changing populations of levels within the ground configuration.
