Nuclear quadrupole moment

{
  "id": "MLC-T-CHM-008113",
  "term": "Nuclear quadrupole moment",
  "field": "Chemistry",
  "definition": "A parameter describing how far a nucleus's charge distribution departs from a sphere, positive for a prolate (cigar-shaped) distribution and negative for an oblate one. Only nuclei with spin quantum number of 1 or more have a nonzero value, and it couples to the electric field gradient at the nucleus. This coupling shows up as quadrupole splitting in Mössbauer spectra and as line broadening or splitting in NMR and nuclear quadrupole resonance.",
  "subject": "Physical and Biophysical Chemistry",
  "see_also": [
    "nucleus"
  ],
  "references": [
    "PAC, 1976, 45, 211. 'Nomenclature and Conventions for Reporting Mössbauer Spectroscopic Data' on page 214 (https://doi.org/10.1351/pac197645030211)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/nuclear-quadrupole-moment/"
}