Direct-semidirect model angular distributions for radiative capture or photonuclear reactions involving nonzero target or residual spins

A recent study of (, n0) reactions on Pb207 and Pb208 produced a direct-semidirect model calculation of the angular distribution (the a2 coefficient) which was vastly different for these two cases. In this paper we offer the formal proof that this is incorrect. It is shown that the angular distribution involving a target with spin is exactly equal to that obtained if the target is treated as spin zero with the residual spin being the single particle total angular momentum in the final state. A corrected calculation for a2 is presented for the case of Pb208(n0)Pb207 and Pb207(n0)Pb206. NUCLEAR REACTIONS Formal derivation of the relationship between the angular distribution for radiative capture involving targets with and without spin for the direct-semidirect model. Errors in the literature are corrected.