Isotope shifts and hyperfine structures of twelve transitions from the high-lying metastable ${}_{}{}^9{}_{}{}^{}$${\mathit{H}}_{\mathit{J}}$ (J=1–7) states of the 4${\mathit{f}}^6$5d6s configuration in Sm i have been measured for the stable isotopes by means of atomic-beam laser spectroscopy. Hyperfine constants A and B for the odd-mass isotopes ${}_{}{}^{147}{}_{}{}^{}\mathrm{Sm}$ and ${}_{}{}^{149}{}_{}{}^{}\mathrm{Sm}$ are determined for the ${}_{}{}^9{}_{}{}^{}$${\mathit{H}}_{\mathit{J}}$ (J=1–7) states and six upper levels of the transitions in Sm i. $J— dependences of the isotope shifts are observed for the 4${\mathit{f}}^6$5d6s ${}_{}{}^9{}_{}{}^{}$H term. Parameters ${\mathit{z}}_{5\mathit{d}}$ of the crossed-second-order effect are derived for the 4${\mathit{f}}^6$5d6s configuration, and ${\mathit{z}}_{5\mathit{d}}$/λ is found to be 165(10) MHz/${\mathrm{fm}}^2$. It has been verified that the field shift is dominant in the crossed-second-order effect.

• Received 13 December 1993

DOI:https://doi.org/10.1103/PhysRevA.49.4398