It has been argued that the role of nuclear couplings in the breakup of neutron-rich weakly bound radioactive beams cannot be neglected. In many instances nuclear breakup should be, in fact, the dominant process responsible for projectile fragmentation. It is thus somewhat puzzling that earlier calculations relying only on the electromagnetic processes did not immediately exhibit their inadequacy. We exploit the case of the reaction ${}^{11}\mathrm{Be}$ on ${}^{208}\mathrm{Pb}$ to advance a possible explanation for this apparent discrepancy.

• Received 2 June 1998

DOI:https://doi.org/10.1103/PhysRevC.59.539