The Hyperfine Structure of Lead

The hyperfine structure of several lines of Pb I and Pb II in the violet and ultraviolet regions has been determined. $\lambda \lambda 4168$, 4062, 4058, 4019, 3739, 3683, 3671, 3639, 3572, 2873, 2833, 2823, 2802 of Pb I, and $\lambda \lambda 4386$, 4245, 3786, 3016, 2948 of Pb II were found to have structure. $\lambda \lambda 2663$, 2614, 2613, and 2577 of Pb I were observed and found to be simple. Exposures with uranium-lead showed that all of the above lines are single for ${\mathrm{Pb}}^{206}$. It was also found from the line patterns that there is a larger abundance of ${\mathrm{Pb}}^{207}$ than ${\mathrm{Pb}}^{208}$ in uranium-lead (Belgian Congo). The hyperfine splittings of $s{}_{}{}^3{}_{}{}^{}P_{0.1}^{}{}_{}{}^{}$ and $p{}_{}{}^3{}_{}{}^{}P_{0,1,2}^{}{}_{}{}^{}$ of ${\mathrm{Pb}}^{207}$ I were calculated. The center of gravity of the ${\mathrm{Pb}}^{207}$ terms and the single ${\mathrm{Pb}}^{206}$ and ${\mathrm{Pb}}^{208}$ terms for these levels were found to fall in the order of their masses. Much larger isotope displacements were observed for Pb II than for Pb I.