Isotope shifts in the resonance line of the arc spectrum of barium

Measurements of the isotope shifts in the resonance line of Ba I of all of the stable isotopes of barium have been made by comparing the wavelengths of the lines, unresolved blends, emitted by enriched isotopes. The shifts relative to $^{138}$Ba are: $^{137}$Ba, 7.7 mK; $^{136}$Ba, 4.2 mK; $^{135}$Ba, 8.4 mK; $^{134}$Ba, 4.6 mK; $^{132}$Ba, 7.4 mK; $^{130}$Ba, 7.8 mK. The shifts for $^{136}$Ba and $^{134}$Ba are in agreement to within 0.1 mK with those found by Razumovski & Chaika (1962), but their values for $^{137}$Ba and $^{135}$Ba are respectively 2.0 and 0.8 mK lower than ours, possibly due to insufficient blending of the weakest hyperfine structure component. The h.f.s. intervals of the terms 6s6p$^1$P$_1$ of the odd isotopes of $^{137}$Ba and $^{135}$Ba have been derived from the results of measurements of the structure of the line emitted by natural barium combined with values of the isotope shifts and the already known ratios of the magnetic moment splitting factors, A, and the quadrupole moment coupling factors, B; approximate values are given of the factors A and B.