In a pseudopotential calculation core electrons are not there so if you want to "see" the core electrons you need to do an all-electron calculation or a PAW calculation where the total charge is reconstructed. If you are interested in knowing a total atomic charge this is easy... just add to the valence electron charge the number of (completely filled) core electrons, change sign and add the nuclear charge.. notice however that the decomposition of a charge distribution in atomic contribution is a somewhat ill defined procedure and Lowdin procedure is just one possibility, so do not attach too much significance to minor changes from system to system...
Something that can be useful to identify bonding in your system can be the analysis of the projected density of states on atomic levels of nearest-neighbor atoms. It is sometime possible to see peaks occurring in the same energy range for the two atoms that signal that electronic states in that energy range are shared between the two atoms as one expect in a covalent bond. Hope it helps. Stefano de Gironcoli David Grifith wrote: > Dear Heather > > Thanks for your comments. I think that this type of charge (Lowdin) which is > nearly the number of valence electrons can not speak about the details of > the system. > Some electrons are bonding and also, the effect of the core (core electron + > nucleus ) is not negligible. I want to compare the real charge of two atoms > in my system with each other not their valence electrons. I appreciate your > help in advance. > > > ------------------------------------------------------------------------ > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum >
