Isotope Shifts in the Spectra of Strontium

The isotope shifts in strontium have been studied in the hollow-cathode spectra from enriched even isotopes with the aid of a Fabry-Perot interferometer. The mass effects show predominance. The field effects are zero within experimental error, with no differential shift between 88-86 and 86-84. The $5p^2{}_{}{}^3{}_{}{}^{}P$ terms are apparently perturbed to the extent that they exhibit a relatively large specific mass effect.