High-resolution laser-rf double-resonance spectroscopy has been performed in the $4f^{6}6s^2{}_{}{}^7{}_{}{}^{}F_6^{}{}_{}{}^{}$ (4020.66 ${\mathrm{cm}}^{-1\mathrm{}}$), $4f^{6}5d6s{}_{}{}^9{}_{}{}^{}H_2^{}{}_{}{}^{}$ (11044.90 ${\mathrm{cm}}^{-1\mathrm{}}$), $4f^{6}5d6s{}_{}{}^9{}_{}{}^{}H_3^{}{}_{}{}^{}$ (11406.50 ${\mathrm{cm}}^{-1\mathrm{}}$), and $4f^{6}5d6s{}_{}{}^7{}_{}{}^{}H_3^{}{}_{}{}^{}$ (13542.80 ${\mathrm{cm}}^{-1\mathrm{}}$) metastable levels of Samarium i. Hyperfine parameters have been deduced with an absolute accuracy of ∼ 2 kHz. By means of laser-induced fluorescence, hyperfine constants have been determined in excited levels up to ∼ 30560 ${\mathrm{cm}}^{-1\mathrm{}}$, and isotope shifts measured for 11 lines.

• Received 19 June 1978

DOI:https://doi.org/10.1103/PhysRevA.19.160