skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Shell structure of superheavy nuclei in self-consistent mean-field models

Abstract

We study the extrapolation of nuclear shell structure to the region of superheavy nuclei in self-consistent mean-field models[emdash]the Skyrme-Hartree-Fock approach and the relativistic mean-field model[emdash]using a large number of parametrizations which give similar results for stable nuclei but differ in detail. Results obtained with the folded-Yukawa potential which is widely used in macroscopic-macroscopic models are shown for comparison. We focus on differences in the isospin dependence of the spin-orbit interaction and the effective mass between the models and their influence on single-particle spectra. The predictive power of the mean-field models concerning single-particle spectra is discussed for the examples of [sup 208]Pb and the spin-orbit splittings of selected neutron and proton levels in [sup 16]O, [sup 132]Sn, and [sup 208]Pb. While all relativistic models give a reasonable description of spin-orbit splittings, all Skyrme interactions show a wrong trend with mass number. The spin-orbit splitting of heavy nuclei might be overestimated by 40[percent][endash]80[percent], which exposes a fundamental deficiency of the current nonrelativistic models. In most cases the occurrence of spherical shell closures is found to be nucleon-number dependent. Spherical doubly magic superheavy nuclei are found at [sub 184][sup 298]114, [sub 172][sup 292]120, or [sub 184][sup 310]126 depending on the parametrization. The Z=114more » proton shell closure, which is related to a large spin-orbit splitting of proton 2f states, is predicted only by forces which by far overestimate the proton spin-orbit splitting in [sup 208]Pb. The Z=120 and N=172 shell closures predicted by the relativistic models and some Skyrme interactions are found to be related to a central depression of the nuclear density distribution. This effect cannot appear in macroscopic-microscopic models or semiclassical approaches like the extended Thomas-Fermi-Strutinski integral approach which have a limited freedom for the density distribution only. In summary, our findings give a strong argument for [sub 172][sup 292]120 to be the next spherical doubly magic superheavy nucleus. [copyright] [ital 1999] [ital The American Physical Society]« less

Authors:
; ; ;  [1];  [2];  [3];  [4]; ; ;  [5]
  1. (Institut fuer Theoretische Physik, Universitaet Frankfurt, Robert-Mayer-Strasse 10, D-60325 Frankfurt (Germany))
  2. (Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599-3255 (United States))
  3. (Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996 (United States))
  4. (Institut fuer Theoretische Physik II, Universitaet Erlangen-Nuernberg, Staudtstrasse 7, D-91058 Erlangen (Germany))
  5. (Joint Institute for Heavy-Ion Research, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831 (United States))
Publication Date:
OSTI Identifier:
6326178
Alternate Identifier(s):
OSTI ID: 6326178
Resource Type:
Journal Article
Journal Name:
Physical Review, C
Additional Journal Information:
Journal Volume: 60:3; Journal ID: ISSN 0556-2813
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; HEAVY NUCLEI; LEAD 208; MEAN-FIELD THEORY; NUCLEAR POTENTIAL; NUCLEAR STRUCTURE; OXYGEN 16; SHELL MODELS; SKYRME POTENTIAL; TIN 132; YUKAWA POTENTIAL; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; EVEN-EVEN NUCLEI; INTERMEDIATE MASS NUCLEI; ISOTOPES; LEAD ISOTOPES; LIGHT NUCLEI; MATHEMATICAL MODELS; MINUTES LIVING RADIOISOTOPES; NUCLEAR MODELS; NUCLEI; NUCLEON-NUCLEON POTENTIAL; OXYGEN ISOTOPES; POTENTIALS; RADIOISOTOPES; SECONDS LIVING RADIOISOTOPES; STABLE ISOTOPES; TIN ISOTOPES 663110* -- General & Average Properties of Nuclei & Nuclear Energy Levels-- (1992-); 663120 -- Nuclear Structure Models & Methods-- (1992-)

Citation Formats

Bender, M., Rutz, K., Maruhn, J.A., Greiner, W., Bender, M., Bender, M., Reinhard, P., Reinhard, P., Maruhn, J.A., and Greiner, W. Shell structure of superheavy nuclei in self-consistent mean-field models. United States: N. p., 1999. Web. doi:10.1103/PhysRevC.60.034304.
Bender, M., Rutz, K., Maruhn, J.A., Greiner, W., Bender, M., Bender, M., Reinhard, P., Reinhard, P., Maruhn, J.A., & Greiner, W. Shell structure of superheavy nuclei in self-consistent mean-field models. United States. doi:10.1103/PhysRevC.60.034304.
Bender, M., Rutz, K., Maruhn, J.A., Greiner, W., Bender, M., Bender, M., Reinhard, P., Reinhard, P., Maruhn, J.A., and Greiner, W. Wed . "Shell structure of superheavy nuclei in self-consistent mean-field models". United States. doi:10.1103/PhysRevC.60.034304.
@article{osti_6326178,
title = {Shell structure of superheavy nuclei in self-consistent mean-field models},
author = {Bender, M. and Rutz, K. and Maruhn, J.A. and Greiner, W. and Bender, M. and Bender, M. and Reinhard, P. and Reinhard, P. and Maruhn, J.A. and Greiner, W.},
abstractNote = {We study the extrapolation of nuclear shell structure to the region of superheavy nuclei in self-consistent mean-field models[emdash]the Skyrme-Hartree-Fock approach and the relativistic mean-field model[emdash]using a large number of parametrizations which give similar results for stable nuclei but differ in detail. Results obtained with the folded-Yukawa potential which is widely used in macroscopic-macroscopic models are shown for comparison. We focus on differences in the isospin dependence of the spin-orbit interaction and the effective mass between the models and their influence on single-particle spectra. The predictive power of the mean-field models concerning single-particle spectra is discussed for the examples of [sup 208]Pb and the spin-orbit splittings of selected neutron and proton levels in [sup 16]O, [sup 132]Sn, and [sup 208]Pb. While all relativistic models give a reasonable description of spin-orbit splittings, all Skyrme interactions show a wrong trend with mass number. The spin-orbit splitting of heavy nuclei might be overestimated by 40[percent][endash]80[percent], which exposes a fundamental deficiency of the current nonrelativistic models. In most cases the occurrence of spherical shell closures is found to be nucleon-number dependent. Spherical doubly magic superheavy nuclei are found at [sub 184][sup 298]114, [sub 172][sup 292]120, or [sub 184][sup 310]126 depending on the parametrization. The Z=114 proton shell closure, which is related to a large spin-orbit splitting of proton 2f states, is predicted only by forces which by far overestimate the proton spin-orbit splitting in [sup 208]Pb. The Z=120 and N=172 shell closures predicted by the relativistic models and some Skyrme interactions are found to be related to a central depression of the nuclear density distribution. This effect cannot appear in macroscopic-microscopic models or semiclassical approaches like the extended Thomas-Fermi-Strutinski integral approach which have a limited freedom for the density distribution only. In summary, our findings give a strong argument for [sub 172][sup 292]120 to be the next spherical doubly magic superheavy nucleus. [copyright] [ital 1999] [ital The American Physical Society]},
doi = {10.1103/PhysRevC.60.034304},
journal = {Physical Review, C},
issn = {0556-2813},
number = ,
volume = 60:3,
place = {United States},
year = {1999},
month = {9}
}