Hyperfine structure and isotope shift of high-lying metastable states of rhenium
Fourteen transitions in ReI, starting from high-lying metastable states belonging to the configurations (5d+6s)7, have been studied by laser-induced fluorescence in a collimated atomic beam, and accurate values for the isotope shifts in these transitions as well as for the hyperfine structure constants of 13 metastable and 9 excited states have been obtained. In addition, high precision measurements of the hyperfine structure of the states 5d5 6s24D7/2 and 5d6 6s6D1/2, 3/2, 5/2, 9/2 have been performed using the atomic beam magnetic resonance technique coupled with laser-induced state-selective detection of metastable atoms. The analysis of the hyperfine structure data yields experimental evidence for far configuration mixing effects on the off-diagonal spin-dipole matrix elements. The phenomenological interpretation of the isotope shifts shows the significance of off-diagonal field-shift effects.