3p-photoionization resonances of atomic Fe, Co, and Ni studied by the observation of singly and doubly charged photoions

Level-resolved Photoionization Cross Sections for Fe i

“…Berrington & Ballance (2001) then investigated the double photoionisation of Fe I by single photon impact by employing the LS R-matrix method. In their ground-term photoionisation cross section of Fe I, they presented large inner-shell resonances around four Rydbergs that were previously observed in the experimental investigations of Bruhn et al (1979), Schmidt et al (1983), andFeist et al (1996). However, at lower energies, their cross sections displayed rather large differences when compared with earlier calculations.…”

“…Existing experimental investigations (e.g., Bruhn et al 1979;Schmidt et al 1983;Feist et al 1996) and a limited number calculations (e.g., Feist et al 1996;Berrington & Ballance 2001) have shown large resonances in the photoionisation cross sections of Fe I around approximately 4 Ryd. These resonances have been attributed to the excitation of a core 3p electron into a vacant 3d orbital, followed by the subsequent emission of a valence 3d electron, i.e., l 3p 3d 4s 3p 3d 4s 3p 3d 4s .…”

Photoionization measurements for the iron isonuclear sequence Fe3+, Fe5+, and FeGharaibeh1, Aguilar2, Covington3 et al. 2011Phys. Rev. A

“…The resulting uncertainty in the energy scale is estimated to be ±0.057 eV. Possible contamination of the 56 Fe 7+ beam with 16 O 2+ ions was estimated by comparing the ratio of the apparent 56 Fe 7+ and 55 Fe 7+ ion-beam currents to the natural relative fractional abundances of these isotopes. The fraction of 56 Fe 7+ was estimated to be 57%.…”

“…The fraction of 56 Fe 7+ was estimated to be 57%. The presence of a significant fraction of 16 O 2+ ions in the primary beam had no effect on the measured relative photoion yield spectrum, since 16 O 3+ and 56 Fe 8+ products do not reach the photoion detector at the same settings of the demerger magnet and signal ion deflector. Their only effect was an initially incorrect normalization of the photoion yield spectrum to the primary ion beam current.…”

“…Ionization of iron ions by electron impact has been extensively studied in crossed-and merged-beams experiments [9][10][11][12][13][14][15]. Photoionization measurements reported for iron include those made for neutral iron [16,17] using synchrotron radiation and an atomic-beam technique. Absolute single-and double-photoionization cross sections for Fe + were measured using a merged-beams technique at photon energies between 15.8 and 180 eV [18] and Fe 4+ between 59 and 140 eV [19].…”