1997/04/09 by P. Möller, P. Moller, J. R. Nix +5 · 30 citations
Engineering · Physics and Astronomy · #Atomic physics #Coulomb #Coulomb barrier #Cross section (physics) #Fission #Fusion #Geology #Geometry #Ground state #Heavy element #Neutron #Nuclear Physics and Applications #Nuclear fusion #Nuclear physics #Nuclear physics research studies #Nuclear reactor physics and engineering #Particle (ecology) #Physics #Saddle point #nucl-th
paper · pdf · doi:10.1007/s002180050399
published in Zeitschrift für Physik A Hadrons and Nuclei 359(3), 251-255 (Springer Nature) · 7 pages. LaTeX. Submitted to Zeitschrift fur Physik A. 5 figures not included here. Complete preprint, including device-independent (dvi), PostScript, and LaTeX versions of the text, plus PostScript files of the figures, available at http://t2.lanl.gov/publications/publications.html or at ftp://t2.lanl.gov/pub/publications/mehep
arxiv created 1997/04/09 · openalex publication_date 1997/09/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Realistic fusion barriers are calculated in a macroscopic-microscopic model for several soft-fusion heavy-ion reactions leading to heavy and superheavy elements. The results obtained in such a realistic picture are very different from those obtained in a purely macroscopic model. For reactions on 208:Pb targets, shell effects in the entrance channel result in fusion-barrier energies at the touching point that are only a few MeV higher than the ground state for compound systems near Z = 110. The entrance-channel fragment-shell effects remain far inside the touching point, almost to configurations only slightly more elongated than the ground-state configuration, where the fusion barrier has risen to about 10 MeV above the ground-state energy. Calculated single-particle level diagrams show that few level crossings occur until the peak in the fusion barrier very close to the ground-state shape is reached, which indicates that dissipation is negligible until very late in the fusion process. Whereas the fission valley in a macroscopic picture is several tens of MeV lower in energy than is the fusion valley, we find in the macroscopic-microscopic picture that the fission valley is only about 5 MeV lower than the fusion valley for soft-fusion reactions leading to compound systems near Z = 110. These results show that no significant ``extra-extra-push'' energy is needed to bring the system inside the fission saddle point and that the typical reaction energies for maximum cross section in heavy-element synthesis correspond to only a few MeV above the maximum in the fusion barrier.