Diode-laser-initiated resonance ionization mass spectroscopy of SmI

Diode-laser-initiated resonant ionization mass spectroscopy (RIMS) was perf ormed for atomic Sm. A single-longitudinal-mode diode laser beam (677.916 n m) was used for the first transition originating from the lowest metastable energy level, 292.6 cm(-1) (4f(6)6s(2) F-7(1)). Excited atoms in the 15039 .6 cm(-1) level (4f(6)6s6p F-9(2)) were ionized by using a pulsed dye laser beam (633.574 nm) due to a two-photon transition via the 30818.8 cm(-1) le vel. We obtained mass spectra which showed a linewidth of about 40 MHz. Thi s result suggests that the resolution was improved more than 10 times compa red to the results obtained using the usual RIMS setup composed of several pulsed lasers and that the diode-laser-initiated RIMS method can be effecti ve in detecting a useful isotope with a small natural abundance. Additional ly, hyperfine constants for the 15039.6 cm(-1) level of Sm-147 and Sm-149 w ere determined using the highly resolved mass spectra.