A study of the dependence of optical model phase shifts on the charge and mass number of the target nucleus

Abstract Analytic expressions are derived for the partial derivatives of the phase shifts and S -matrix elements, obtained from an optical model potential, with respect to the charge and nucleon number of the target nucleus. The partial derivatives can be used to obtain linear approximations to phase shifts and S -matrix elements in which the charge or nucleon number has been changed by plus or minus one unit.