Photoionization measurements for the iron isonuclear sequence Fe3+, Fe5+, and Fe7+

Authors

M. F. Gharaibeh, University of Nevada - Reno
A. Aguilar, Lawrence Berkeley National LaboratoryFollow
A. M. Covington, University of Nevada - RenoFollow
E. D. Emmons, University of Nevada - Reno
S. W. J. Scully, University of Nevada - Reno
R. A. Phaneuf, University of Nevada - RenoFollow
A. Muller, Universitat Giessen
J. D. Bozek, Lawrence Berkeley National Laboratory Berkeley
A. L. D. Kilcoyne, Lawrence Berkeley National LaboratoryFollow
A. S. Schlachter, Lawrence Berkeley National Laboratory BerkeleyFollow
I. Alvarez, Universidad Nacional Autonoma de Mexico
C. Cisneros, Universidad Nacional Autonoma de MexicoFollow
G. Hinojosa, Universidad Nacional Autónoma de MéxicoFollow

Date of this Version

2011

Citation

PHYSICAL REVIEW A 83, 043412 (2011); DOI: 10.1103/PhysRevA.83.043412

Abstract

Cross sections for single photoionization of Fe³⁺, Fe⁵⁺, and Fe⁷⁺ ions were measured at spectral resolutions of 0.04, 0.15, and 0.13 eV, respectively, by merging mass- and charge-selected ion beams with a beam of monochromatized synchrotron undulator radiation. The measurements span photon energy ranges beginning at the ionization thresholds and extending several tens of electron volts to include the most important resonant contributions due to 3p–nd transitions to autoionizing states. The photoion yield spectra are characterized by narrow resonances and also broad features in Fe³⁺ and Fe⁵⁺ that are believed to result from unresolved fast super- Coster-Kronig transitions following 3p–3d excitation. Absolute photoionization cross-section measurements were also performed using ion beams containing undetermined fractions of ions in their ground and metastable states. A Rydberg series attributed to 3p–nd transitions from the ²G₁ metastablestate in Fe³⁺ was identified. The data are compared with recently published measurements on Fe³⁺ and Fe⁵⁺ using a similar technique at lower spectral resolution.