Mechanisms of heavy-ion induced ( p , n )- and ( n , p )-type reactions

Excitation functions and recoil ranges for the reactions $sup 65$Cu($sup 12$C,X)$sup 65$Zn and $sup 65$Cu($sup 11$B,X)$sup 65$Zn were measured for $sup 12$C ion energies between 43 and 122 MeV and for $sup 11$B ion energies between 60 and 115 MeV. The angular distribution for the production of $sup 65$Zn by the $sup 65$Cu($sup 12$C,X)$sup 65$Zn reaction was determined at 88.6 MeV. The forward projected recoil ranges are not in satisfactory agreement with ranges which would be predicted on the basis of the complete fusion compound nucleus mechanism nor apparently with a simple kinematic treatment of the quasielastic scattering model. The experimental results appear to be consistent with a charge- exchange or nucleon transfer mechanism in which the distance of closest approach varies inversely with incident energy. Evidence for the enhancement of isospin $delta$T = 0 transitions to target analog states is suggested in that only an upper limit could be placed on the production of cross sections of $sup 65$Ni, a $delta$T not-equal to 0 product, compared to high yields for $sup 65$Zn, a $delta$T = 0 product. (AIP)