Electric Field Gradient at Ta in Group-IVBMetals. I.α-Zirconium

The first part of a program to investigate the nuclear electric quadrupole interaction at Ta in the group-IV $B$ transition metals is reported. We have found, for Ta in hcp $\alpha$-zirconium at room temperature, an interaction frequency ${\nu }_Q$ (482-keV state in ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}$) = 312±3 MHz using the time-differential perturbed-angular-correlation technique. This corresponds to an electric field gradient at Ta in $\alpha -\mathrm{Z}\mathrm{r}$ of $\mathrm{}\left|\mathrm{eq}\right|=(5.1\mathrm{}\pm 0.2)\times {10}^{17}$ V/${\mathrm{cm}}^2$. The results indicate a substantial electronic contribution to the magnitude and temperature dependence of the field gradient.