HYPERFINE ANOMALY IN THE Z6P7/2 LEVEL OF THE 4F76S6P CONFIGURATION OF EUROPIUM-I

The hyperfine interaction constants of the z P726 and z P728 levels of the configuration 4f 6s76p of the isotopes Eu151 and Eu153 have been remeasured with the laser-atomic-beam technique. The analysis yields values of -6.80(26)% and -1.00(3)%, respectively, for the hyperfine anomalies. The anomaly in the z P726 level is the largest so far observed and deviates considerably from the ground-state hyperfine anomaly. The experimental values of the hyperfine anomaly are compared with a calculation based on Nilsson-type nuclear wave functions. Possibly the electronic-state dependence of the hyperfine anomaly is due to core polarization. © 1980 The American Physical Society.