Photoionization of [Formula Presented] ions by synchrotron radiation: Measurements and absolute cross sections in the photon energy range 23–68 eV

S. Schippers, A. Müller, S. Ricz, M. E. Bannister, G. H. Dunn, A. S. Schlachter, G. Hinojosa, C. Cisneros, A. Aguilar, A. M. Covington, M. F. Gharaibeh, R. A. Phaneuf

Research output: Contribution to journalArticlepeer-review

Abstract

Cross sections for the photoionization (PI) of [Formula Presented] ions with [Formula Presented] ground-state configuration have been measured by employing the merged ion-photon beams method. The [Formula Presented] ions were produced from metallic vapor in an electron cyclotron resonance ion source, and the photon beam was generated by an undulator in the electron-synchrotron storage ring of the advanced light source of the Lawrence Berkeley National Laboratory. The experimental photon energy range 23–68 eV encompasses the direct [Formula Presented] and [Formula Presented] photoionization thresholds. The experimental photoion spectrum is dominated by autoionizing resonances due to [Formula Presented] excitations predominantly decaying via Coster-Kronig and super-Coster-Kronig transitions. Individual resonances located around [Formula Presented] have been measured with an instrumental energy spread [Formula Presented] as low as 1.2 meV, corresponding to a resolving power of [Formula Presented] around 33 500. The fractions of metastable ions in the [Formula Presented] ion beam are obtained by comparing the photoionization cross section with the recently measured [Schippers et al., Phys. Rev. A 65, 042723 (2002)] cross section for the time-reversed process of photorecombination of [Formula Presented] ions. Absolute strengths of several [Formula Presented] and [Formula Presented] PI resonances have been determined. They are the same as the corresponding resonance strengths for isoelectronic [Formula Presented] ions.

Original languageEnglish
Pages (from-to)13
Number of pages1
JournalPhysical Review A - Atomic, Molecular, and Optical Physics
Volume67
Issue number3
DOIs
StatePublished - 2003

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