  One-neutron halo nuclei, composed by a weakly-bound particle coupled to a
core nucleus, are studied within a particle-plus-core model. A semi-microscopic
method to generate the two-body Hamiltonian of such a system, including core
excitation, is proposed. The method consists in generating the spin-independent
part of the valence-core interaction using a single-folding procedure,
convoluting a realistic nucleon-nucleon (NN) interaction with the core
transition densities. The latter are calculated with the Antisymetrized
Molecular Dynamics (AMD) method. The prescription is applied to the well known
halo nucleus, $^{11}$Be, as a test case. The results show an important
predictive power that opens a door to the understanding of other lesser known
halo nuclei. In order to show the potential usefulness of the method, it is
applied to analyze the structure of $^{19}$C.
