Studies of Fusion in the SILICON-28 + Silicon -28, SILICON-28 + SILICON-30 and SILICON-30 + SILICON-30 Reactions

Excitation functions for the yields of all the residual nuclei from the ('28)Si+('28)Si, ('28)Si+('30)Si and ('30)Si+('30)Si reactions have been measured for center of mass energies in the region within one to two times the Coulomb barrier using steps of 500 keV in the laboratory system. Thirteen, twelve and fourteen elements were identified for each reaction, respectively, including the light elements ('31)P and ('34)S in ('28)Si+('30)Si and ('34)S, ('36)Cl, ('37)Cl and ('37)Ar in ('30)Si+('30)Si, whose origin is not clear. While no structure is shown by the data for the ('28)Si+('28)Si reaction, we have found evidence for intermediate width structure in the 2(alpha) and (alpha)pn channels in ('28)Si+('30)Si and for broad structure in the total fusion cross sections for ('30)Si+('30)Si. Calculations using a barrier penetration model with one free parameter reproduce the experimental results quite well. Evaporation model calculations indicate that the individual structure of the nuclei involved in the respective decay chains might have an important influence upon the deexcitation process at the energies relevant to our experiments.