Results for forward angle unpolarized scattering in the energy range 100 eV to 10 keV show that the primary differences between the cross sections are for configurations with different numbers of K electrons. All neutral configurations with six electrons have a common high energy limit for the forward cross section, given by the form factor value. Moving down in energy towards the K edge the cross sections separate according to the number of K electrons, giving rise to three groupings, with the larger cross sections being associated with more Kelectrons. This reflects the influence of the K anomalous amplitudes.
In the region below the K resonances (but above the L edge) the situation is more complex. Again there is a overall separation of cross sections according to the number of K electrons, as the K electrons are no longer contributing to scattering in this region. But in this case it is the configurations with fewer K electrons that now have the larger cross sections. For a given number of K electrons, having more electrons in the L2/L3 subshells tends to enhance the cross section, reflecting the influence of the strong L2/L3 to K dipole allowed resonance. A cross section may or may not exhibit a deep minima just below this resonance as a result of interference between the real subshell amplitudes. If however the configuration is such that there is a net downward number of these transitions such a minima does not appear, and the cross section is much larger than the ground state result, which does have such a minimum.
The usual numerical method of performing a summation, weighted by the number of electrons which are present, over magnetic quantum numbers at the level of the scattering amplitude is exact for fully-filled subshells, but not for partially-filled shells. We have investigated the corrections obtained by treating the dominant electric dipole amplitude for the partially-filled inner shells exactly, and found them to be small in most of the studied energy range. This is due to the large contribution to the amplitude from the remaining fully-filled subshells. One situation in which the corrections are important is in regions where the averaged-amplitude approach can give a near-zero minimum in the cross section, such as just below the resonance region, where these corrections can even dominate the cross section. For the case of ionic excited states, where there are only a few electrons, all in partially-filled subshells, these considerations will also be more important.