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Title: Three-photon resonance ionization of atomic Mn in a hot-cavity laser ion source using Ti:sapphire lasers

We have demonstrated three-photon resonance ionization of atomic manganese (Mn) in a hot-cavity ion source using Ti: sapphire lasers. Three-step ionization schemes employing different intermediate levels and Rydberg or autoionizing (AI) states in the final ionization step are established. Strong AI resonances were observed via the 3d54s5s f6S5/2 level at 49 415.35 cm-1, while Rydberg transitions were reached from the 3d54s4d e 6D9/2,7/2,5/2) levels at around 47 210 cm-1. Analyses of the strong Rydberg transitions associated with the 3d54s4d e 6D7/2 lower level indicate that they belong to the dipole-allowed 4d → nf69/2,7/2,5/2 series converging to the 3d54s 7S3 ground state of Mn II. From this series, an ionization potential of 59 959.56 ± 0.01 cm-1 is obtained for Mn. At high ion source temperatures the semi-forbidden 4d → nf8F°9/2,7/2,5/2 series was also observed. The overall ionization efficiency for Mn has been measured to be about 0.9% when using the strong AI transition in the third excitation step and 0.3% when employing an intense Rydberg transition. Experimental data indicate that the ionization efficiency was limited by the interaction of Mn atoms with ion source materials at high temperatures.
Authors:
 [1] ;  [2] ;  [2] ;  [2]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Physics Division
  2. Johannes Gutenberg Univ., Mainz (Germany). Dept. of Physics
Publication Date:
OSTI Identifier:
1261435
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Journal of Physics. B, Atomic, Molecular and Optical Physics
Additional Journal Information:
Journal Volume: 48; Journal Issue: 11; Journal ID: ISSN 0953-4075
Publisher:
IOP Publishing
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26); German Federal Ministry of Education and Research (BMBF)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS resonant laser ionization; Ti:sapphire laser; manganese; laser ion source; hot cavity