The mechanism of the Coulomb breakup reactions of the nuclei with neutron-halo structure is investigated in detail. A time-dependent Schrödinger equation for the halo neutron is numerically solved by treating the Coulomb field of a target as an external field. The momentum distribution and the post-acceleration effect of the final fragments are discussed in a fully quantum mechanical way to clarify the limitation of the intuitive picture based on the classical mechanics. The theory is applied to the Coulomb breakup reaction of ${}_{}{}^{11}{}_{}{}^{}\mathrm{Be}$${+}^{208}$Pb. The breakup mechanism is found to be different between the channels of ${\mathit{j}}^{\mathrm{\pi }}$=1/$2^{\mathrm{-}}$ and 3/$2^{\mathrm{-}}$, reflecting the underlying structure of ${}_{}{}^{11}{}_{}{}^{}\mathrm{Be}$. The calculated result reproduces the energy spectrum of the breakup fragments reasonably well, but explains only about a half of the observed longitudinal momentum difference. © 1996 The American Physical Society.

• Received 26 December 1995

DOI:https://doi.org/10.1103/PhysRevC.53.2296