  Proton and neutron density profiles of 760 nuclei in the mass region of
A=16-304are analyzed using the Skyrme energy density for the parameter set
SLy4. Simple formulae are obtained to fit the resulting radii and diffuseness
data. These formulae may be useful to estimate the values of the unmeasured
radii, and especially in extrapolating charge radius values for nuclei which
are far from the valley of stability or to perform analytic calculations for
bound and/or scattering problems. The obtained neutron and proton
root-mean-square radii and the neutron skin thicknesses are in agreement with
the available experimental data.
