{
  "annotation_id": "587eaf2d-3cc6-4f55-957c-8f056e9eef62",
  "date_created": "2026-03-02T18:01:04.217000Z",
  "date_modified": "2026-03-02T18:01:04.217000Z",
  "file_hash": "04f8684b6305943fe79e9cc4b7f87474334e695fbdafd484587eb34d6892f33c",
  "private": false,
  "record": {
    "abstract": "Atomic quadrupole moments and hyperfine constants of the metastable $^2\nD_{3/2, 5/2}$ states of Ca$^+$, Sr$^+$, Ba$^+$, Yb$^+$, and Hg$^+$ are\ncalculated by the multiconfiguration Dirac-Hartree-Fock and relativistic\nconfiguration-interaction methods. For Hg$^+$, the configuration is $5d^9\n6s^2$. For the other ions, the configuration consists of a single $d$-electron\noutside a set of closed shells. Current interest in the quadrupole moments of\nthese states is due to the fact that optical transitions of these ions may be\nuseful as references for frequency standards. Energy shifts of the metastable\nstates due to the interactions of the quadrupole moments with external electric\nfield gradients are among the largest sources of error in these frequency\nstandards. For the quadrupole moments, agreement is obtained to within about\n10~% with the available measurements. For the hyperfine constants, good\nagreement is obtained with measurements and with other calculations, except for\nthe $A$ factors of the $^2D_{5/2}$ states of Sr$^+$, Ba$^+$, and Yb$^+$, where\nthe correlation effects are so large that they reverse the sign of the constant\nrelative to the Dirac-Hartree-Fock value. As a test of the Hg$^+$ calculational\nmethods, quadrupole moments and hyperfine constants are calculated for the\n$5d^9 6s^2 ^2 D_{3/2, 5/2}$ states in isoelectronic neutral Au. This yields a\nnew value of the nuclear quadrupole moment $Q$($^{197}$Au) = +0.587(29) b.",
    "arxiv_id": "physics/0512250",
    "authors": [
      "W. M. Itano"
    ],
    "categories": [
      "physics.atom-ph"
    ],
    "doi": "10.1103/PhysRevA.73.022510",
    "journal_ref": "Physical Review A 73, 022510 (2006)",
    "title": "Quadrupole moments and hyperfine constants of metastable states of   Ca$^+$, Sr$^+$, Ba$^+$, Yb$^+$, Hg$^+$, and Au",
    "url": "https://arxiv.org/abs/physics/0512250"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "3844a89f-5620-44fb-b23a-2f8b40f39c9f",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}