  The halo factor is one of the experimental data which describes a
distribution of neutrons in nuclear periphery. In the presented paper we use
Skyrme-Hartree (SH) and the Relativistic Mean Field (RMF) models and we
calculate the neutron excess factor $\Delta_B$ defined in the paper which
differs slightly from halo factor $f_{\rm exp}$. The results of the
calculations are compared to the measured data.
