Quadrupole coupling atIr193nuclei in iron

Mössbauer-source experiments on Fe(${}_{}{}^{193}{}_{}{}^{}\mathrm{Os}$) alloys with less than 0.1-at.% osmium show that quadrupole coupling persists in domains at high dilution, thereby confirming and extending the earlier NMR results of Aiga and Itoh on wall resonances and the Mössbauer results of Wagner and Potzel on a more concentrated alloy. Arguments are presented to show that a Mössbauer spectrum on a more concentrated alloy can yield a reasonably accurate value of $e^{2}qQ$, including its sign, even in the presence of substantial solute-solute-induced magnetic and quadrupole perturbations. For the ground state of ${}_{}{}^{193}{}_{}{}^{}\mathrm{Ir}$ in iron, this work yielded $\frac{e^{2}qQ}{2h}=-2.05\mathrm{}\left(25\right)\mathrm{}$ ${\nu }_0=119.6\mathrm{}\left(3\right)\mathrm{}$ MHz, and $H_{\mathrm{hf}}=1481\mathrm{}\left(4\right)\mathrm{}$ kOe.