A microscopical DWBA description of the charge-exchange reactions ( 7Li, 7Be)

Abstract

The charge-exchange reaction ( 7Li, 7Be is described in the frame of a microscopical DWBA with central effective forces. The transition density for 7Li- 7Be is calculated in two ways: with a one-particle model and with a cluster model, taking full account of recoil effects. The formalism is used for the cases of ( 7Li, 7Be reactions with 6Li and 40Ca. Further cross sections for reactions on 12C and 16O with E( 7 Li) = 78 MeV and excitation energies around 4.5 and 6.2 MeV, respectively, are compared to new data obtained at the Kurchatov Institute. Here particle-hole states in an oscillator model were used to characterize the heavy system. Angular distributions are well reproduced, but absolute cross sections are 6–7 times too small. This indicates that the assumption of a direct one-step process is correct, but that tensor forces should be included as a component of the effective nucleon-nucleon force.