A parameter which describes the effective shape of the equivalent ellipsoid of the nuclear charge distribution, Q > 0 for prolate (e.g.
57Fe,
197Au); Q < 0 for oblate (e.g.
119Sn,
129I) nuclei.
Source:
PAC, 1976, 45, 211. 'Nomenclature and Conventions for Reporting Mössbauer Spectroscopic Data' on page 214 (https://doi.org/10.1351/pac197645030211)