Mass Division in Nuclear Fission and Isotope Effect

• Published in: Journal of Nuclear Science and Technology Vol. 39; no. 4; pp. 332 - 336
• Main Authors: IWAMOTO, Akira, MÖLLER, Peter, MADLAND, David G., SIERK, Arnie J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Tokyo Taylor & Francis Group 01.04.2002; Atomic Energy Society of Japan
• Subjects: bimodal fission; Exact sciences and technology; Fermium isotopes; Fission reactions; isotope effects; mass division; nuclear fission; Nuclear physics; Nuclear reactions: specific reactions; Physics; potential energy surface; saddle point method; Theoretical study; Fermium isotopes; Potential energy surfaces; Isotope effects; Nuclear fission; Saddle point
• ISSN: 0022-3131; 1881-1248
• DOI: 10.1080/18811248.2002.9715198

The theoretical calculations on the most probable mass division in nuclear fission process are given. The model is based on the topographical analysis of the five-dimensional potential energy surface of more than 2.5 million mesh points. Special attention is paid to obtain the energies and deformations of the saddle points without using any approximation. The calculation tells us that there exist multiple saddle points in the static potential energy surface. The lowest and the next lowest saddle point play an important role for the fission process. Of these two saddle points, one is mass-symmetrically deformed and the other is mass-asymmetrically deformed and the relative heights of these two saddle points depend on the fissioning nuclei. In case of Fm isotopes, the relative height of two saddle points appears very sensitively, i.e., 256 Fm has asymmetrically deformed lowest saddle point and in 258 Fm, the lowest saddle point is symmetrically deformed. This feature explains the phenomenon called bimodal fission.