Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Transitions between the $4f$-core-excited states in Ir$^{16+}$,
  Ir$^{17+}$, and Ir$^{18+}$ ions for clock applications   Iridium ions near $4f$-$5s$ level crossings are the leading candidates for a
new type of atomic clocks with a high projected accuracy and a very high
sensitivity to the temporal variation of the fine structure constant $\alpha$.
To identify spectra of these ions in experiment accurate calculations of the
spectra and electromagnetic transition probabilities should be performed.
Properties of the $4f$-core-excited states in Ir$^{16+}$, Ir$^{17+}$, and
Ir$^{18+}$ ions are evaluated using relativistic many-body perturbation theory
and Hartree-Fock-Relativistic method (COWAN code). We evaluate excitation
energies, wavelengths, oscillator strengths, and transition rates. Our
large-scale calculations includes the following set of configurations:
$4f^{14-k}5s^{m}5p^{n}$ with $(k+m+n)$ equal to 3, 2, and 1 for the Ir$^{16+}$,
Ir$^{17+}$, and Ir$^{18+}$ ions, respectively. The $5s-5p$ transitions are
illustrated by the synthetic spectra in the 180 - 200 \AA range. Large
contributions of magnetic-dipole transitions to lifetimes of low-lying states
in the region below 2.5 Ry are demonstrated.

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The categories of this paper are: chao-dyn
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The categories of this paper are: patt-sol
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The categories of this paper are: q-bio
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The categories of this paper are: stat
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The categories of this paper are: hep-ph
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The categories of this paper are: adap-org
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The categories of this paper are: plasm-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: atom-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: comp-gas
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The categories of this paper are: cs
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-ex
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The categories of this paper are: solv-int
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The categories of this paper are: alg-geom