CW laser excitation of the barium 6sng and 6snh Rydberg series from the metastable 6s5d1.3D and 5d21G4states

Abstract
Accurate level energies of the 6sng 1G4, 3G3,4,5(n>or=6) and 6snh 1H5, 3H5 (n>or=10) Rydberg series of neutral barium have been determined in a CW laser-atomic beam experiment. The even parity 6sng series are studied in a two-step excitation 6s5d to 5d6p to 6sng using two CW dye lasers. All levels of the 5d7d configuration, which perturb the 6sng energy positions, are also observed. The odd parity 6snh levels are excited in one step starting from the thus far unknown 5d21G4 level. This level, located at 24696.278 cm-1, turns out to be metastable. Its hyperfine structure and the isotope shifts of all stable even isotopes have been measured.