Shape evolution in collision between very heavy ions and potential pockets

The evolution of the shape degrees of freedom, namely necking and deformation, has been studied in a classical dynamical model using the proximity nuclear interactions and the Coulomb interaction for the conservative forces and with wall and window frictions as the dissipative forces. The systems 238U + 238U at 700 and 800 MeV and 208Pb + 208Pb at 650 MeV centre-of-mass energies have been considered. Though the total interaction energy has pockets for certain shapes of the dinuclear complex, the dynamically evolved shapes do not have such pockets and the reaction time is typically approx. 10-21s as in deep inelastic collisions. (author)