  We study isoscalar (IS) and isovector (IV) densities in ${}^{40} \mathrm{Ca}$
in comparison with theoretical densities calculated by Skyrme Hartree-Fock (HF)
models. The charge symmetry breaking and the charge independence breaking
forces are introduced to study the effect on the IV density. The effect of
isospin mixing in the ground-state density is examined by using the
particle-vibration coupling model taking into account the collective IV giant
monopole excitation. We show a clear correlations in the IV density and isospin
impurity of ${}^{40} \mathrm{Ca}$ within the HF and the particle-vibration
coupling model. We extract for the first time the experimental information of
isospin impurity from the magnitude of IV density.
