HFS SEPARATIONS AND HFS ANOMALIES IN THE $sup 2$P/1 OVER 2/ STATE OF Ga$sup 69$, Ga$sup 71$, Tl$sup 203$, AND Tl$sup 20$$sup 6$

By use of the method of atomic beam magnetic resonance, the ground-state hyperfine structure splittings in the two common gallium and thallium isotopes have been measured. The measured values are: $\ensuremath{\Delta}\ensuremath{\nu}({\mathrm{Ga}}^{69})=(2677.9875\ifmmode\pm\else\textpm\fi{}0.0010)\ifmmode\times\else\texttimes\fi{}{10}^{6}$ ${\mathrm{sec}}^{\ensuremath{-}1}$, $\ensuremath{\Delta}\ensuremath{\nu}({\mathrm{Ga}}^{71})=(3402.6946\ifmmode\pm\else\textpm\fi{}0.0013)\ifmmode\times\else\texttimes\fi{}{10}^{6}$ ${\mathrm{sec}}^{\ensuremath{-}1}$, $\ensuremath{\Delta}\ensuremath{\nu}({\mathrm{Tl}}^{203})=(21105.447\ifmmode\pm\else\textpm\fi{}0.005)\ifmmode\times\else\texttimes\fi{}{10}^{6}$ ${\mathrm{sec}}^{\ensuremath{-}1}$, and $\ensuremath{\Delta}\ensuremath{\nu}({\mathrm{Tl}}^{205})=(21310.835\ifmmode\pm\else\textpm\fi{}0.005)\ifmmode\times\else\texttimes\fi{}{10}^{6}$ ${\mathrm{sec}}^{\ensuremath{-}1}$. A comparison of the ratio of the dipole coupling constants in the ground state of the two isotopes with the ratio of the nuclear ${g}_{I}$ factors yields the hfs anomaly. Theoretical and experimental values of the anomaly are compared.