Role of ²⁸Si excitations in the sub-barrier fusion of ²⁸Si+ ¹²⁰Sn

Fusion cross sections were measured for the systems ¹⁶O and ²⁸Si+ ¹²⁰Sn in order to understand the role of specific channels involved in sub-barrier fusion. Fusion cross sections were measured by direct detection of the evaporation residues. Extracted fusion barrier distributions were analyzed using the exact coupled-channel code CCFULL as well as the simplified code CCMOD. These calculations show that the observed fusion barrier distribution for the Si+Sn system is reproduced only if the rotational excitation in ²⁸Si is taken into account.