A momentum space methodology is presented for calculating second order distorted wave Born approximation matrix elements without the use of the zero-range approximation. This methodology is applied to the sequential transfer term in ($p,t$) reactions. Examples are presented for ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}\mathrm{}(p,t)\mathrm{}{}_{}{}^{206}{}_{}{}^{}\mathrm{Pb}$ which show that: (1) finite-range effects can be large, (2) the shape of the calculated differential cross section can be strongly dependent on the contribution from a sequential transfer mechanism, and (3) the post-prior interchange usually used is probably the best realistic approximation.

NUCLEAR REACTIONS ($p$-$d$,$d$-$t$), finite range, momentum space techniques; ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}(p,t)E=35\mathrm{}$ MeV; calculated $\sigma \left(\theta \right)$; simultaneous plus sequential transfer, both finite range.

• Received 26 February 1976

DOI:https://doi.org/10.1103/PhysRevC.14.506