ENERGY-DEPENDENCE OF 2-STEP (P,T) CROSS-SECTIONS

The energy dependence of two-step distorted-wave Born approximation calculations is studied for unnaturalparity state excitations by the (p, t) reaction involving (p, p′, t), (p, t, t′), and (p, d, t) processes. The calculations which provide rapidly decreasing cross sections with an increase in the incident energy are found to be quite consistent with the observed results for the O18(p, t)O16 (8.88 MeV, 2-) reaction at the energy range of Ep=20-45 MeV. The remarkable difference of kinematical features between one-step and twostep processes is pointed out and the importance of higher-order effects for one-step allowed transitions is apparently indicated. NUCLEAR REACTIONS Energy dependence of second-order DWBA cross sections, O18(p, t)O16 (8.88 MeV, 2-) and (9.85 MeV, 2+) E=20.0-43.6 MeV. © 1978 The American Physical Society.