Radiative proton capture study of the giant dipole resonance inCo55,57

Extensive yield-curve and angular-distribution measurements have been made for the ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}(p,{\gamma }_0)$ and the ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}(p,{\gamma }_0)$ reactions. Both yield curves clearly show the envelope of the giant dipole resonance. The giant resonance appears to be broader in ${}_{}{}^{57}{}_{}{}^{}\mathrm{Co}$ and this is attributed to a greater isospin splitting and to the fact that proton emission from the two isospin components is expected to be more nearly equal. In both cases the angular distributions appear to be somewhat different for the two $T$ components with the difference greater in ${}_{}{}^{57}{}_{}{}^{}\mathrm{Co}$.