Resonant ionization spectroscopy of autoionizing Rydberg states in cobalt and redetermination of its ionization potential

Journal Article · 20 March 2017 · Journal of Physics. B, Atomic, Molecular and Optical Physics

DOI: https://doi.org/10.1088/1361-6455/aa58d0 · OSTI ID:1361301

Liu, Yuan ^[1]; Gottwald, T. ^[2]; Mattolat, C. ^[2]; Wendt, K. ^[2]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Physic Division
2. Johannes Gutenberg Univ., Mainz (Germany). Inst for Physics

We obtained multi-step resonance ionization spectroscopy of cobalt using a hot-cavity laser ion source and three Ti:Sapphire lasers. Furthermore, the photoionization spectra revealed members of five new autoionizing Rydberg series that originate from three different lower levels of 3d⁷4s5s h⁴F_9/2, 3d⁷4s4d f⁴G_11/2, and 3d⁷4s4d f⁴H_13/2 and converge to the first four excited states of singly ionized Co. Our analyses of the Rydberg series yield 63564.689 0.036 cm^-1 as the first ionization potential of Co, which is an order of magnitude more accurate than the previous estimation. Using a three-step resonance ionization scheme that employs an autoinizing Rydberg state in the last transition, we obtained an overall ionization efficiency of about 18% for Co.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1361301
• Journal Information: Journal of Physics. B, Atomic, Molecular and Optical Physics, Vol. 50, Issue 7; ISSN 0953-4075
• Publisher: IOP PublishingCopyright Statement
• Country of Publication: United States
• Language: English