Multipole expansions in exact finite-range calculations of two-nucleon transfer reactions between heavy ions

A method is developed for calculating microscopic form factors for two-nucleon transfer reactions between heavy ions in the distorted-wave Born approximation. This method utilizes a multipole expansion of the two-nucleon overlap integrals in terms of the relative angular momentum of a transferred nucleon pair, which is found to converge very rapidly. Sample calculations are carried out for the reaction 48Ca(18O,16O)50Ca at E/sub lab/ = 50 MeV, leading to the ground and excited states. The calculations underpredict the experimental cross sections by a factor of about 10 for 0+1, 2+1, and 2+2 state transitions. It is also also found that the singlet (S = 0) and triplet (S = 1) two-nucleon transfers contribute about equally to the cross section