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J/ApJ/849/5 L-edge single and multiple photoionization of Fe+ (Schippers+, 2017)

Near L-edge single and multiple photoionization of singly charged iron ions. Schippers S., Martins M., Beerwerth R., Bari S., Holste K., Schubert K., Viefhaus J., Savin D.W., Fritzsche S., Muller A. <Astrophys. J., 849, 5 (2017)> =2017ApJ...849....5S
ADC_Keywords: Atomic physics Keywords: atomic data; atomic processes; line: identification; line: profiles; ISM: atoms; opacity Abstract: Absolute cross-sections for m-fold photoionization (m=1, ..., 6) of Fe+ by a single photon were measured employing the photon-ion merged-beams setup PIPE at the PETRA III synchrotron light source, operated by DESY in Hamburg, Germany. Photon energies were in the range 680-920eV, which covers the photoionization resonances associated with 2p and 2s excitation to higher atomic shells as well as the thresholds for 2p and 2s ionization. The corresponding resonance positions were measured with an uncertainty of ±0.2eV. The cross-section for Fe+ photoabsorption is derived as the sum of the individually measured cross-sections for m-fold ionization. Calculations of the Fe+ absorption cross-sections were carried out using two different theoretical approaches, Hartree-Fock including relativistic extensions and fully relativistic multiconfiguration Dirac-Fock. Apart from overall energy shifts of up to about 3eV, the theoretical cross-sections are in good agreement with each other and with the experimental results. In addition, the complex de-excitation cascades after the creation of inner-shell holes in the Fe+ ion were tracked on the atomic fine-structure level. The corresponding theoretical results for the product charge-state distributions are in much better agreement with the experimental data than previously published configuration-average results. The present experimental and theoretical results are valuable for opacity calculations and are expected to pave the way to a more accurate determination of the iron abundance in the interstellar medium. Description: The present experiment on the photoionization of Fe+ ions was carried out at the Photon-ion Spectrometer setup at PETRA III (PIPE; Figure 1). PETRA III is presently the brightest third-generation synchrotron light source worldwide. It is operated by DESY in Hamburg, Germany. The experimental arrangement and procedures have been described previously (Schippers+ 2014JPhB...47k5602S ; Mueller+ 2017ApJ...836..166M). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 157 1200 Measured cross sections
See also: J/A+AS/97/443 : Fluorescence for Be to Zn (Kaastra+ 1993) J/A+AS/109/125 : Photoionisation cross section (Verner+, 1995) J/ApJ/700/1299 : Gas-phase element depletions in the ISM (Jenkins, 2009) J/ApJ/808/174 : FeII radiative transition rates (Bautista+, 2015) J/ApJ/813/16 : Fe7+ ionization cross section (Hahn+, 2015) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 7 F7.3 eV E [680.9/921.1] Photon energy 9- 15 F7.5 Mbarn sig1 [0.008/2.6] Cross section for 1-fold photoionization of Fe+ ions 17- 23 F7.5 Mbarn e_sig1 [0.003/0.02] Statistical experimental uncertainty in sig1 (1) 25- 31 F7.5 Mbarn sig2 [0.1/3.3] Cross section for 2-fold photoionization of Fe+ ions 33- 39 F7.5 Mbarn e_sig2 [0.001/0.02] Statistical experimental uncertainty in sig2 (1) 41- 47 F7.5 Mbarn sig3 [0.03/4.7] Cross section for 3-fold photoionization of Fe+ ions 49- 55 F7.5 Mbarn e_sig3 [0.001/0.02] Statistical experimental uncertainty in sig3 (1) 57- 63 F7.5 Mbarn sig4 [0/0.6]? Cross section for 4-fold photoionization of Fe+ ions 65- 75 E11.5 Mbarn e_sig4 [0/0.008]? Statistical experimental uncertainty in sig4 (1) 77- 87 E11.5 Mbarn sig5 [0/0.1]? Cross section for 5-fold photoionization of Fe+ ions 89- 99 E11.5 Mbarn e_sig5 [0/0.003]? Statistical experimental uncertainty in sig5 (1) 101-112 E12.5 Mbarn sig6 [-3.3e-05/0.006] Cross section for 6-fold photoionization of Fe+ ions 114-124 E11.5 Mbarn e_sig6 [1.4e-05/0.0004] Statistical experimental uncertainty in sig6 (1) 126-133 F8.5 Mbarn sigT [0/11]? Total cross section for m-fold photoionization of Fe+ ions 135-141 F7.5 Mbarn e_sigT [0/0.03]? Statistical experimental uncertainty in sigT (1) 143-149 F7.5 --- q [0/4.3]? Mean product charge-state, Eq. 2, Fig. 8b 151-157 F7.5 --- e_q [0/0.03]? Statistical experimental uncertainty in q
Note (1): The systematic uncertainties of the energy and cross-section scales are ±0.2eV and ±15% (at 90% confidence level), respectively.
History: From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 13-Jun-2018
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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