Nuclear Moments and Isotope Shifts of ${\mathrm{Tl}}^{199}$, ${\mathrm{Tl}}^{200}$, ${\mathrm{Tl}}^{201}$, ${\mathrm{Tl}}^{202}$, and ${\mathrm{Tl}}^{204}$—Isotope Shifts in Odd-Odd Nuclei

The hyperfine-structure separations and isotope shifts of several radioactive isotopes of thallium have been measured by optical spectroscopic techniques. The results are: ${\mu }^{199}=1.57\mathrm{}$ nm; ${\mu }^{201}=1.58\mathrm{}$ nm; and both $\left|{\mu }^{200}\right|$ and $\left|{\mu }^{202}\right|<~0.15$ nm. The isotope-shift measurements, which include the first data of this kind obtained for heavy odd-odd nuclei, permitted a comparison of the relative isotope shifts for isotones in mercury and thallium. A marked similarity in the shifts was observed.