Energy dependence of the (p, n) analog cross sections of the molybdenum isotopes between 16 and 26 MeV

The differential cross sections for the ($p, n$) reaction to the ground-state analogs of the seven stable Mo isotopes have been measured for proton energies between 16 and 26 MeV. Integrated cross sections are found to deviate from the expected linear dependence on neutron excess. In addition, the excitation functions show a resonant-type enhancement at about 20 MeV. The ($N-Z$) dependence and energy dependence are not consistent with several possible explanations for deviations from the simple charge exchange model. However, the ($N-Z$) dependence for the even isotopes can be explained in part by the effects of multistep processes.