Coupled-channel Dispersive Global Optical Model

The purpose of this thesis is to give a global dispersive optical potential for axially symmetric deformed even-even nuclei in the target mass region of A=24-122 up to 200 MeV, and then apply this potential to the analysis of nucleon-induced scattering data.Firstly we applied rigid-rotator model considering only nuclear levels belonged to the ground-state rotational band to the analysis of nuclear level structures for axially symmetric deformed nuclei of A=24-122 mass range, in order to obtain the nuclear wave functions of ground-state and excited states. These wave functions are incorporated into the dispersive coupled-channel optical model for analyzing the nucleon-induced scattering data. Secondly, to obtain the global dispersive optical potential, we performed the local parameters searching for seven nuclei: ²⁸Si, ⁴⁸Ti, ⁵⁶Fe, ⁵⁸Ni, ⁹⁰Zr, ⁹⁶Mo, ¹²⁰Sn by using the code OPTMAN. After local parameters obtained, we fitted them by simple functional form of the target mass number to obtain global forms of dispersive optical potential parameters which have smooth dependencies of potential parameters and geometry parameters on the target mass number. With this global dispersive potential, we made a large number of calculations for ^24,26Mg, ^28,30Si, ³²S, ⁴⁰Ar, ⁴⁰Ca, ⁵²Cr, ⁽54,56_Fe, ^58,60,62Ni, ^90,92Zr,^92,94,96,98Mo and ^{116,118,120,122}Sn to testthe validity and limitation of present model at a wider range of incident energies and target-nuclei. The numerical results show generally good agreement with available data of neutron total cross sections, neutron/proton elastic and inelastic angular distributions, and proton reaction cross sections. Finally, in order to show the prediction power of different model calculations, we compared the results of our model with the data of evaluated data library, such as LA150, as well as the calculations of other models, such as spherical model and distorted wave Bonn approximation (DWBA) approach. Comparison shows that present model is preferable than spherical model and DWBA approach, especially for the calculations of the inelastic scattering angular distributions for 4⁺levels. In addition, some calculations of analyzing power by present model were performed to show the prediction of analyzing power, and the calculated results are in well agreement with the experimental data.