On the topography of potential-energy surfaces for heavy-ion reactions

Abstract

Potential-energy surfaces have been calculated for heavy-ion fusion and deep-inelastic reactions as a function of the c.m. distance, the neck size, the eccentricity of the nuclei and their mass asymmetry. An extended liquid-drop model has been used which properly accounts for effects of a diffuse nuclear surface and the finite range of the nuclear two-body interaction. The position of interaction barriers, fission barriers and scission lines is discussed as a function of the total mass, the mass asymmetry, and the angular momentum of the total system. It is shown that the concept of an interaction barrier becomes ambiguous for systems with a total charge larger than about seventy. It is also shown that scission of heavy, mass-asymmetric systems is likely to occur at larger c.m. distances than the scission of symmetric systems with the same total mass. The potential for the mass-transfer degree of freedom is investigated for contact configurations and the boundaries of the fusion region have been determined as a function of the total charge, the mass asymmetry and the angular momentum of the system.