Heavyelement fission barriers
(2009) In Physical Review C (Nuclear Physics) 79(6). Abstract
 We present calculations of fission properties for heavy elements. The calculations are based on the macroscopicmicroscopic finiterange liquiddrop model with a 2002 parameter set. For each nucleus we have calculated the potential energy in three different shape parametrizations: (1) for 5 009 325 different shapes in a fivedimensional deformation space given by the threequadraticsurface parametrization, (2) for 10 850 different shapes in a threedimensional deformation space spanned by epsilon(2), epsilon(4), and gamma in the Nilsson perturbedspheroid parametrization, supplemented by a densely spaced grid in epsilon(2), epsilon(3), epsilon(4), and epsilon(6) for axially symmetric deformations in the neighborhood of the ground state,... (More)
 We present calculations of fission properties for heavy elements. The calculations are based on the macroscopicmicroscopic finiterange liquiddrop model with a 2002 parameter set. For each nucleus we have calculated the potential energy in three different shape parametrizations: (1) for 5 009 325 different shapes in a fivedimensional deformation space given by the threequadraticsurface parametrization, (2) for 10 850 different shapes in a threedimensional deformation space spanned by epsilon(2), epsilon(4), and gamma in the Nilsson perturbedspheroid parametrization, supplemented by a densely spaced grid in epsilon(2), epsilon(3), epsilon(4), and epsilon(6) for axially symmetric deformations in the neighborhood of the ground state, and (3) an axially symmetric multipole expansion of the shape of the nuclear surface using beta(2), beta(3), beta(4), and beta(6) for intermediate deformations. For a fissioning system, it is always possible to define uniquely one saddle or fission threshold on the optimum trajectory between the ground state and separated fission fragments. We present such calculated barrier heights for 1585 nuclei from Z=78 to Z=125. Traditionally, actinide barriers have been characterized in terms of a "doublehumped" structure. Following this custom we present calculated energies of the first peak, second minimum, and second peak in the barrier for 135 actinide nuclei from Th to Es. However, for some of these nuclei which exhibit a more complex barrier structure, there is no unique way to extract a doublehumped structure from the calculations. We give examples of such more complex structures, in particular the structure of the outer barrier region near Th232 and the occurrence of multiple fission modes. Because our complete results are too extensive to present in a paper of this type, our aim here is limited: (1) to fully present our model and the methods for determining the structure of the potentialenergy surface, (2) to present fission thresholds for a large number of heavy elements, (3) to compare our results with the twohumped barrier structure deduced from experiment for actinide nuclei, and (4) to compare to additional fissionrelated data and other fission models.</p>. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/record/1462351
 author
 Moller, Peter; Sierk, Arnold J.; Ichikawa, Takatoshi; Iwamoto, Akira; Bengtsson, Ragnar ^{LU} ; Uhrenholt, Henrik ^{LU} and Åberg, Sven ^{LU}
 organization
 publishing date
 2009
 type
 Contribution to journal
 publication status
 published
 subject
 in
 Physical Review C (Nuclear Physics)
 volume
 79
 issue
 6
 publisher
 American Physical Society
 external identifiers

 wos:000267701200015
 scopus:67249159616
 ISSN
 05562813
 DOI
 10.1103/PhysRevC.79.064304
 language
 English
 LU publication?
 yes
 id
 9fe9ed7d22354b2e91e6903a2bddfc3d (old id 1462351)
 date added to LUP
 20090820 12:02:24
 date last changed
 20171217 03:45:19
@article{9fe9ed7d22354b2e91e6903a2bddfc3d, abstract = {We present calculations of fission properties for heavy elements. The calculations are based on the macroscopicmicroscopic finiterange liquiddrop model with a 2002 parameter set. For each nucleus we have calculated the potential energy in three different shape parametrizations: (1) for 5 009 325 different shapes in a fivedimensional deformation space given by the threequadraticsurface parametrization, (2) for 10 850 different shapes in a threedimensional deformation space spanned by epsilon(2), epsilon(4), and gamma in the Nilsson perturbedspheroid parametrization, supplemented by a densely spaced grid in epsilon(2), epsilon(3), epsilon(4), and epsilon(6) for axially symmetric deformations in the neighborhood of the ground state, and (3) an axially symmetric multipole expansion of the shape of the nuclear surface using beta(2), beta(3), beta(4), and beta(6) for intermediate deformations. For a fissioning system, it is always possible to define uniquely one saddle or fission threshold on the optimum trajectory between the ground state and separated fission fragments. We present such calculated barrier heights for 1585 nuclei from Z=78 to Z=125. Traditionally, actinide barriers have been characterized in terms of a "doublehumped" structure. Following this custom we present calculated energies of the first peak, second minimum, and second peak in the barrier for 135 actinide nuclei from Th to Es. However, for some of these nuclei which exhibit a more complex barrier structure, there is no unique way to extract a doublehumped structure from the calculations. We give examples of such more complex structures, in particular the structure of the outer barrier region near Th232 and the occurrence of multiple fission modes. Because our complete results are too extensive to present in a paper of this type, our aim here is limited: (1) to fully present our model and the methods for determining the structure of the potentialenergy surface, (2) to present fission thresholds for a large number of heavy elements, (3) to compare our results with the twohumped barrier structure deduced from experiment for actinide nuclei, and (4) to compare to additional fissionrelated data and other fission models.</p>.}, author = {Moller, Peter and Sierk, Arnold J. and Ichikawa, Takatoshi and Iwamoto, Akira and Bengtsson, Ragnar and Uhrenholt, Henrik and Åberg, Sven}, issn = {05562813}, language = {eng}, number = {6}, publisher = {American Physical Society}, series = {Physical Review C (Nuclear Physics)}, title = {Heavyelement fission barriers}, url = {http://dx.doi.org/10.1103/PhysRevC.79.064304}, volume = {79}, year = {2009}, }