Hyperfine structure and lifetimes of the 4P322 and 5P322 states of K39

The hyperfine constants of the 4P322 and 5P322 states of K39 have been measured using the optical level-crossing method. The results are: a(4P322)=2.0±0.1 Mc/sec; b(4P322)=2.9±0.2 Mc/sec; a(5P322)=1.95±0.05 Mc/sec; b(5P322)=0.92±0.1 Mc/sec. These hfs constants are accurately proportional to the fine structure intervals to within 1%. These data, and the results from previous measurements on the P122 states, yield values for the ratio a(P12)a(P32) in good agreement with measurements on other alkali atoms. The calculated quadrupole moment is Q=(0.053±0.008)×10-24 cm2, including Sternheimer corrections. The life-times of these states were determined to be: τ(4P322)=26.0±0.5 nsec and τ(5P322)=140.8±1.0 nsec. © 1968 The American Physical Society.