GLOBAL CALCULATION OF NUCLEAR SHAPE ISOMERS

P. MÖLLER and A. J. SIERK
Theoretical Division, Los Alamos National Laboratory, New Mexico 87545, USA

R. BENGTSSON
Department of Mathematical Physics, Lund Institute of Technology,
SE-22100 Lund, Sweden

H. SAGAWA
Center for Mathematical Sciences, University of Aizu Aizu-Wakamatsu, Fukushima 965-80, Japan

T. ICHIKAWA
RIKEN Nishina Center, Riken, Wako, Saitama, 351-0198, Japan

This paper is published in Physical Review Letters 103 (2009) 212501
The copy here is from the PRL web site
It has been assigned Los Alamos National Laboratory Preprint No LA-UR-09-05683)



Abstract:

Nuclear shape isomers are well-known in the Kr and Pb regions. To evaluate how prevalent shape isomers are across the nuclear chart we use a well-benchmarked macroscopic-microscopic model to calculate potential-energy surfaces as functions of spheroidal ε2, hexadecapole ε4, and axial-asymmetry γ, shape coordinates for 7206 nuclei from A = 31 to A = 290. We analyze these and identify the deformations and energies of all minima deeper than 0.2 MeV. The results allow us to identify nuclei in which {\it shape isomers} may be experimentally observed. We find that the vast majority of nuclear shape isomers occur in the A = 80 region, the A = 100$ region, and in a more extended region centered around 208Pb. We compare our model to experimental data for a sequence of Kr isotopes and find encouraging agreement, motivating our global calculation. Our main results are presented in a contour diagram versus N and Z, which for each nucleus shows the number of minima obtained. The results reveal one fairly unexplored region of shape isomerism, which is experimentally accessible, namely the region north-east of 208Pb, that is Z > 82 and N > 126 .

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Peter Moller
Last modified Thu July 5, 2012