Speaker
Prof.
William Walters
(University of Maryland)
Description
The structures of semi-magic 70Ni42 and 72Ni44 were investigated following complementary multinucleon-transfer and secondary fragmentation reactions. Changes to the higher-spin, presumed negative-parity states based on observed γ-ray coincidence relationships improve the agreement with shell-model calculations using effective interactions in the neutron f5/2•p•g9/2 model space. The second 2+ and (4+) states in 70Ni42 can only be successfully described when proton excitations across the Z = 28 shell gap are included. Monte-Carlo shell-model calculations suggest that the latter two states are part of a prolate-deformed intruder sequence, establishing an instance of shape coexistence at excitation energies lower than those observed recently in neighboring 68Ni40.
Including U. of Maryland ANL - MSU - U. of Tokyo - U. of Padua - LBNL - U. of Edinburgh - U. of Aizu Orsay – JAEA - Central Michigan U collaboration
Based on work supported in part by the USDOE (DE-FG02-94ER40834, DE-AC02-06CH11357, DE- AC02-05CH11231), NSF (PHY-1102511), and NNSA (DE-NA0000979).
Primary author
Prof.
William Walters
(University of Maryland)
Co-authors
Prof.
Alexandra Gade
(Michigan State University)
Dr
C. J. Chiara
(University of Maryland, ANL)
Dr
Dirk Weisshaar
(Michigan State University)
Ms
Jessica Harker
(University of Maryland)
Dr
Robert Janssens
(Argonne National Laboratory)
Prof.
Takaharu Otsuka
(University of Tokyo)
Dr
Yusuke Tsunoda
(University of Tokyo)
