Hyperfine Structure of the6s6pP11Level of the Stable Ytterbium Isotopes

Abstract

The techniques of level-crossing and anticrossing spectroscopy have been applied in a study of the hfs of the excited $6s6p{}_{}{}^1{}_{}{}^{}P_1^{}{}_{}{}^{}$ level of the stable ytterbium isotopes. Details concerning the anticrossing signal, its nature, shape, intensity, and dependence on polarized light are given. The values we infer for the hfs constants are $\frac{A\left({}_{}{}^1{}_{}{}^{}P_1^{}{}_{}{}^{}\right)}{g_J}=206.0\mathrm{}\left(16\right)\mathrm{}$ Mc/sec for ${\mathrm{Yb}}^{171}$ ($I=\frac{1}{2}$) and $\frac{A\left({}_{}{}^1{}_{}{}^{}P_1^{}{}_{}{}^{}\right)}{g_J}=56.9\mathrm{}\left(5\right)\mathrm{}$ Mc/sec, $\frac{B\left({}_{}{}^1{}_{}{}^{}P_1^{}{}_{}{}^{}\right)}{g_J}=575\mathrm{}\left(7\right)\mathrm{}$ Mc/sec for ${\mathrm{Yb}}^{173}$ ($I=\frac{5}{2}$). The measured values for the ${}_{}{}^1{}_{}{}^{}P_1^{}{}_{}{}^{}$ level are compared with those calculated from the known hfs constants of the ${}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}$ and ${}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{}$ levels. Fair agreement is obtained with predictions based on the modified Breit-Wills theory given by Lurio.