Nucleus-nucleus potential in the two-center shell model

The 16O—16O potential which describes elastic scattering is calculated from the microscopic point of view in the two-center shell model without spin-orbit coupling developed by the Greiner group. The use of variational method can determine the dependence of the oscillator frequency ω(R) on the separation distance and also correct the inadequate asymptotic behaviour in Greiner's approach. We discuss the possibility of the formation of nuclear molecule during the collision on the basis of the estimation of the time for nucleon exchange, and also the changeability of the configuration describing the 16O+16O system by use of the time-dependent perturbation method. This discussion suggests that the collision process is neither adiabatic nor sudden, but intermediate. It is shown that very shallow potential similar to the one obtained by optical model analysis of experimental data can be obtained under the conditions that the two-body force reproduces the saturation properties and that the wave function is totally antisymmetrized. The distortion effects such as the dependence of the frequency ω(R) on the separation distance and the tunnelling of surface nucleons are discussed.