Two-neutron halo structure of 31F.

We apply the Gamow shell model to study 25-31F isotopes. As both internucleon correlations and continuum coupling are properly treated therein, the structure shape of 31F at large distance can be analyzed precisely. For this, one-nucleon densities, root-mean-square radii, and correlation densities are calculated in neutron-rich fluorine isotopes. It is then suggested that 31F exhibits a two-neutron halo structure, built from both continuum coupling and nucleon-nucleon correlations. [ABSTRACT FROM AUTHOR]