The isovector/isoscalar ratio of the imaginary part of the intermediate-energy nucleon optical model potential studied by the quantum molecular dynamics

Energy dependence of the ratio of the isovector and isoscalar strengths in the imaginary part of the nucleon optical model potential at the medium energy range was extracted from an analysis of proton and neutron induced total reaction cross sections on 11Li with a theoretical framework called quantum molecular dynamics (QMD). The isovector/isoscalar ratio was found to be about 0.8 at 100 MeV, and decreased almost linearly in log(E) to 0 at several hundred MeV. This results was consistent with an estimate at lower energy, and was also in good accord with the values used by Kozack and Madland for the analysis of nucleon + 208Pb reactions. (author)