Nuclear Spins of Neutron-deficient Promethium, Samarium, Europium and Gadolinium Isotopes

Abstract

Spin-measurements have been performed on some neutron-deficient promethium, samarium, europium and gadolinium isotopes using conventional atomic-beam magnetic resonance techniques. The results are: 141Pm (20.9 min) I=5/2, 140Sm (14.8 min) I=0, 141Sm (11.3 min) I=1/2, 141mSm (22.9 min) I=11/2, 142Sm (72.5 min) I=0, 143Sm (8.8 min) I=3/2, 145Eu (5.93 d) I=5/2, 146Eu (4.65 d) I=4, 147Eu (22 d) I=5/2, 148Eu (54 d) I=5, 149Eu (93.1 d) I=5/2, 150Eu (12.6 h) I=0, 145Gd (22.9 min) I=1/2, 147Gd (38.5 h) I=7/2, 149Gd (9.4 d) I=7/2, 151Gd (120 d) I=7/2. The investigated nuclei appear close to the shell closure at neutron number N=82. A systematic review of the low-lying states of odd-even and doubly-odd nuclei in this region is presented.