In summary, optical models are essential in nuclear physics for understanding the interactions between particles and nuclei. These models take into account the varying optical potential that particles experience as they approach a nucleus, providing a more accurate representation of the scattering processes involved. They also allow for the prediction of nuclear reactions and the study of nuclear structure. Without optical models, our understanding of nuclear physics would be limited and hindered.
You will also need to do a better job of explicitly stating your question. I don't even understand what you mean by optical model. I don't understand what context you mean by "need"