Microscopic study of the nucleus-nucleus optical potential based on the Feshbach's projection operator formalism

The nucleus-nucleus optical potential is discussed microscopically for wide energy region. As the origin of the absorptive part of the potential, the roles of the mean field excitation and the nucleon-nucleon collision are discussed in detail. It is shown that the mean field excitation plays decisive role for low energy region while the nucleon-nucleon collision becomes dominant for high energy region. Total reaction cross section is calculated with the microscopically obtained optical potential. In the intermediate energy region, the energy dependence of the total reaction cross section comes dominantly from the decrease of the mean field excitation. (author)