  A new ATSP2K module is presented for evaluating the electron density function
of any multiconfiguration Hartree-Fock or configuration interaction wave
function in the non relativistic or relativistic Breit-Pauli approximation. It
is first stressed that the density function is not a priori spherically
symmetric in the general open shell case. Ways of building it as a spherical
symmetric function are discussed, from which the radial electron density
function emerges. This function is written in second quantized coupled
tensorial form for exploring the atomic spherical symmetry. The calculation of
its expectation value is performed using the angular momentum theory in
orbital, spin, and quasispin spaces, adopting a generalized graphical
technique. The natural orbitals are evaluated from the diagonalization of the
density matrix.
