Nuclear quadrupole moments from molecular microwave data: The quadrupole moment of85Rband87Rbnuclei and survey of molecular data for alkali-metal nuclei

Abstract

The ``molecular'' values of the quadrupole moment of the Rb and Na nuclei have been obtained by using spectroscopic values of nuclear coupling constants and high-level-correlated relativistic calculations of the electric-field gradients in fluorides and chlorides. The recommended value for the ${}^{85}\mathrm{Rb}$ nucleus which follows from the present study is about 276 mb, with expected error bars of the order of about 1 mb. This value agrees with the atomic spectroscopy data, and suggests that the quadrupole coupling constant measured for the RbCl molecule is in error. The present calculations for ${}^{23}\mathrm{Na}$ confirm the earlier molecular result for its electric quadrupole moment, and combined with recent atomic calculations lead to the recommended value in the range 104--105 mb. The molecular results for nuclear quadrupole moments of the alkali-metal nuclei are reviewed leading to a list of the corresponding recommended values.