Isotope Shift and Hyperfine Structure of the Neutron-Deficient Thallium Isotopes

The measurement of the isotope shift and hyperfine structure of the neutron-deficient thallium isotopes has been extended to isotopes $196m$, 195, and $194m$. The isotope shifts are $\Delta (196m-205)=-288\pm 4$ mK, $\Delta (195\mathrm{}-205)=-274\pm 4$ mK, and $\Delta (194m-205)=-346\pm 4$ mK in the 5350 A line. (1 mK = ${10}^{-3\mathrm{}}$ ${\mathrm{cm}}^{-1\mathrm{}}$.) In the 3776 Å line, the shifts are $\Delta (196m-205)=-288\pm 10$ mK, $\Delta (195\mathrm{}-205)=-249\pm 4$ mK and $\Delta (194m-205)=-348\pm 10$ mK. The derived dipole moment of thallium-195 is $(1.55\mathrm{}\pm 0.04){\mu }_N$. The shifts in the thallium sequence are compared with the shifts in the mercury sequence.