Hyperfine splittings and isotope shifts of (6s)21S0 → (6s6p) 1P1 transition in barium

Abstract

The hyperfine and isotope shifts of the (6s)21S0 → (6s6p) 1P1 transition in barium were measured using a ring dye laser to excite an atomic beam. The laser frequency was scanned across the transition while fluorescence produced by the radiative decay of the excited state was detected. The frequency was calibrated using an acousto-optic modulator to frequency shift part of the laser beam. The spectrum therefore consisted of pairs of peaks separated by the modulation frequency. The shifts (MHz) relative to 138Ba are 137Ba F = 5/2, 63.43 ± 0.25; 135Ba F = 5/2, 120.55 ± 0.25; 136Ba, 128.02 ± 0.39; 137Ba F = 3/2, 274.56 ± 0.09; 135Ba, 323.44 ± 0.19; and 135,137Ba F = 1/2, 549.47 ± 0.12 where the transition in 138Ba occurs at the lower frequency. The magnetic dipole a and electric quadrupole b hyperfine coupling constants (MHz) of the (6s6p) 1P1 state were determined to be a135 = −98.16 ± 0.14, b135 = 34.01 ± 0.22, a137 = −109.50 ± 0.13, and b137 = 50.09 ± 0.21.