  The properties of the deformed halo of 31Ne were discussed using the
antisymmetrized molecular dynamics plus resonating group method (AMD+RGM). The
AMD+RGM calculations describe a large neutron radius for the ground state and
reveal that the ground state is dominated by core-excited components. The
resonant states were also investigated by applying the analytical continuation
of the coupling constant. It was found that the first excited state (the 5/2-
state) is also dominated by core-excited components and has a small decay
width, whereas the second excited state (the 7/2- state) is dominated by the
valence neutron in the $f$-wave coupled to the ground state of 30Ne.
