HYPERFINE SPECTRA OF THE RADIOACTIVE ISOTOPES KR-81 AND KR-85

Isotope shifts and hyperfine constants are reported for the radioactive isotopes Kr-81 and Kr-85 and the stable isotope Kr-83. The previously unreported nuclear moments of Kr-81 were determined to be mu(I) = -0.909(4) nuclear magneton and Q= +0.630(13) b from the hyperfine constants. This work increases the number of transitions for which Kr-85 hyperfine constants and isotope shifts have been measured from 1 to 4. The hyperfine anomaly for krypton reported in the previous measurement of Kr-85 hyperfine constants [H. Gerhardt et al., Hyperfine Interact. 9, 175 (1981)] is not supported by this work. The isotope shifts and hyperfine constants of Kr-83 measured in this work are in excellent agreement with previous work. Saturation spectroscopy was used to study transitions from krypton's metastable 1s5 state to the 2p9, 2p7, and 2p6 states. In saturation spectra, different line shapes were observed for the even- and odd-mass krypton isotopes. This even- versus odd-line-mass shape difference can be explained using the large cross section that has been reported for collisional transfer of the 1s5 state excitation between krypton atoms. Two-color two-photon laser-induced fluorescence was used to measure the hyperfine spectra of the 1s5-4d4' transition using the 2p9 state as the intermediate state. This technique proved to be more sensitive than saturation spectroscopy.