Hyperfine Structure and Isotope Shift in Barium

Abstract

Spectroscopic hyperfine structure studies with separated isotopes of barium have definitely confirmed a nuclear spin $\frac{3}{2}$ for the odd isotopes ${\mathrm{Ba}}^{135}$ and ${\mathrm{Ba}}^{137}$. The lines of the even isotopes show no structure. The isotope shift is linear among masses of the same parity, but there is a relatively great odd-even shift: Note the order 138, 136, 134, 137, 135 in BaI, and 138, 136, 137, 134, 135 in BaII. The relative positions of the components (centroids, for odd masses) of the resonance lines, in ${10}^{-3\mathrm{}}$±0.7.${10}^{-3\mathrm{}}$ ${\mathrm{cm}}^{-1\mathrm{}}$ are