Recent developments in frequency metrology and optical clocks have been based on
electronic transitions in atoms and singly charged ions as references. The control over all …

Highly charged ions (HCIs) constitute a large class of atomic systems since each element
has as many ionization states as it has protons—in a sense, this extends the periodic table …

We report the first direct laboratory measurement of the spontaneous emission due to the
hyperfine splitting of the ground state of a highly charged hydrogenlike ion excited by …

We present the results of an experimental study of magnetic dipole (M 1) transitions in highly
charged argon ions (Ar x, Ar xi, Ar xiv, Ar xv) in the visible spectral range using an electron …

The energy levels and observed spectral lines of ionized argon atoms, in all stages of
ionization, have been compiled. Sufficient experimental data were found to generate level …

Promising searches for new physics beyond the current standard model (SM) of particle
physics are feasible through isotope-shift spectroscopy, which is sensitive to a hypothetical …

This paper surveys the ongoing physics experiments at the Electron Beam Ion Trap (EBIT)
facility at NIST, with particular attention paid to the underlying physical principles involved. In …

State-of-the-art optical clocks achieve precisions of 10− 18 or better using ensembles of
atoms in optical lattices, or individual ions in radio-frequency traps,. Promising candidates …

Metastable states in an atomic energy-level structure greatly influence atomic processes in
plasmas. In particular, high-energy long-lived metastable levels brought about by 5 s and 4 f …

We have constructed an electron-beam ion trap (EBIT) to facilitate the creation and study of
highly charged ions. After a brief introduction to EBITs in general, we describe the design of …