Hyperfine structure separation and magnetic moment of K42

The atomic beam flop-in magnetic-resonance method has been employed to measure the hyperfine structure separation Δν and the nuclear magnetic moment μI in the S122 electronic ground state of the 12.4-h potassium-42. The results are: Δν(K42)=1258.877(4) Mc/sec; μI(K42)=-1.1395(30) nuclear magnetons (diamagnetic correction not included). With these values, estimates of the hyperfine structure anomaly with respect to other potassium isotopes can be made: Δ4239=+0.20(25)%, Δ4240=-0.25(25)%, Δ4241=+0.42(25)%. © 1964 The American Physical Society.