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Title: Four-valence-proton yrast states in 1 /sub 68//sup 50/Er/sub 82/

Journal Article · · Phys. Rev. C; (United States)

The level structure of the four-valence-proton N = 82 nucleus /sup 150/Er has been studied by ..gamma..-ray spectroscopy following reactions of 225--255 MeV /sup 58,60/Ni beams on /sup 92,94,95/Mo and /sup 93/Nb targets. Yrast levels in /sup 150/Er are established up to 9.5 MeV excitation energy; they include isomeric levels at 2797, 7372, and 9509 keV. The observed levels up to 5222 keV are interpreted in terms of shell model configurations involving the four valence protons outside the /sup 146/Gd core. They include states with dominant seniority two and four configurations ..pi..h/sub 11/2//sup 4/, ..pi..h/sub 11/2//sup 3/s/sub 1/2/, and ..pi..h/sub 11/2//sup 3/d/sub 3/2/, and octupole excitations. The levels above 5222 keV must involve excitation of the /sup 146/Gd core, and they are not interpreted in detail. The energies of the ..pi..h/sub 11/2//sup 4/ levels are found to agree reasonably with predictions based on empirical two-body interactions taken from the ..pi..h/sub 11/2//sup 2/ spectrum of /sup 148/Dy. Even better agreement is obtained by taking account also of the known ..pi..h/sub 11/2//sup 3/ energies in /sup 149/Ho. The dependence of E2 transition probabilities in N = 82 nuclei on the ..pi..h/sub 11/2/ subshell occupation number is discussed.

Research Organization:
Purdue University, West Lafayette, Indiana 47907
OSTI ID:
6620153
Journal Information:
Phys. Rev. C; (United States), Vol. 29:6
Country of Publication:
United States
Language:
English