Abstract
We measure optical spectra of Nd-like W, Re, Os, Ir, and Pt ions of particular interest for studies of a possibly varying fine-structure constant. Exploiting characteristic energy scalings we identify the strongest lines, confirm the predicted 5s-4f level crossing, and benchmark advanced calculations. We infer two possible values for optical M2/E3 and E1 transitions in Ir17+ that have the highest predicted sensitivity to a variation of the fine-structure constant among stable atomic systems. Furthermore, we determine the energies of proposed frequency standards in Hf12+ and W14+.
Original language | English |
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Article number | 150801 |
Journal | Physical Review Letters |
Volume | 114 |
Issue number | 15 |
DOIs | |
State | Published - 16 Apr 2015 |