Rotational and vibrational excitations of colliding nuclei in a three-stage classical molecular dynamics simulation

For nuclei with significant static deformation the reorientation of the deformed nucleus plays a key role in near-barrier collisions. Using a Classical Rigid Body Dynamics (CRBD) model for 24Mg + 208Pb system it is shown that due to the Coulomb reorientation of the deformed nucleus, the isotropy of the initial orientations is modified. It is also shown that the extent of reorientation of the deformed nucleus depends not only on the initial orientation of the axis of symmetry of the deformed nucleus but it also depends strongly on the collision energy. Due to the rigid-body constraint in the CRBD-model the two colliding nuclei, however, can not come very close together and the transfer of energy from the relative motion to internal excitation is explicitly neglected. This leads to no bound state formation of the two colliding nuclei in most of the cases. In such cases, however, passing over the barrier is assumed to be resulting in fusion. Fusion cross sections are calculated using the Wong's formula with energy and orientation dependent barrier parameters