Nuclear-Quadrupole Interactions in Perovskite-Type Compounds ofHf181Studied by the Perturbed-Angular-Correlation Technique

Measurements of nuclear-quadrupole-interaction constants in perovskite-type compounds of PbHf${\mathrm{O}}_3$, SnHf${\mathrm{O}}_3$, CaHf${\mathrm{O}}_3$, and SrHf${\mathrm{O}}_3$ have been performed using the perturbed-angular-correlation technique. A range of fundamental frequencies from 150×${10}^6$ to 550×${10}^6$ rad/sec was determined. The variation of the quadrupole constants has been discussed through the molecular-orbital theory. A semiempirical formula for the admixture coefficient between $d$ wave functions and $p$ wave functions which describes the covalent bonding present in each $\mathrm{AB}{\mathrm{O}}_3$ compound has been derived.