Cluster expression in fission and fusion in high-dimensional macroscopic-microscopic calculations

Conference · Thu Jan 01 00:00:00 EST 2004

DOI:https://doi.org/10.1016/j.nuclphysa.2004.04.096· OSTI ID:977405

Iwamoto, A ^[1]; Ichikawa, T ^[2]; Moller, P ^[3]; Sierk, A J ^[4]

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1. Akira
2. Takatoshi
3. Peter
4. Arnold J.

We discuss the relation between the fission-fusion potential-energy surfaces of very heavy nuclei and the formation process of these nuclei in cold-fusion reactions. In the potential-energy surfaces, we find a pronounced valley structure, with one valley corresponding to the cold-fusion reaction, the other to fission. As the touching point is approached in the cold-fusion entrance channel, an instability towards dynamical deformation of the projectile occurs, which enhances the fusion cross section. These two 'cluster effects' enhance the production of superheavy nuclei in cold-fusion reactions, in addition to the effect of the low compound-system excitation energy in these reactions. Heavy-ion fusion reactions have been used extensively to synthesize heavy elements beyond actinide nuclei. In order to proceed further in this direction, we need to understand the formation process more precisely, not just the decay process. The dynamics of the formation process are considerably more complex than the dynamics necessary to interpret the spontaneous-fission decay of heavy elements. However, before implementing a full dynamical description it is useful to understand the basic properties of the potential-energy landscape encountered in the initial stages of the collision. The collision process and entrance-channel landscape can conveniently be separated into two parts, namely the early-stage separated system before touching and the late-stage composite system after touching. The transition between these two stages is particularly important, but not very well understood until now. To understand better the transition between the two stages we analyze here in detail the potential energy landscape or 'collision surface' of the system both outside and inside the touching configuration of the target and projectile. In Sec. 2, we discuss calculated five-dimensional potential-energy landscapes inside touching and identify major features. In Sec. 3, we present calculated 'collision surfaces' for still separated targets and projectiles. Implications for SHE formation are discussed. Section 4 is a short summary of the present analysis.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE
• OSTI ID: 977405
• Report Number(s): LA-UR-04-0284; LA-UR-04-284; TRN: US1002915
• Resource Relation: Journal Volume: 738; Conference: Submitted to: The 8th International Conference on Clustering Aspects of Nuclear Structure and Dynamics, Nov. 24-29, 2003, Nara, Japan
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
74 ATOMIC AND MOLECULAR PHYSICS
ACTINIDE NUCLEI
COLD FUSION
CONFIGURATION
CROSS SECTIONS
DECAY
DEFORMATION
EXCITATION
FISSION
HEAVY NUCLEI
INSTABILITY
NUCLEAR STRUCTURE
NUCLEI
POTENTIAL ENERGY
PRODUCTION
PROJECTILES
SPONTANEOUS FISSION
TARGETS