Dear Steve, Indeed, you are freezing the core electrons in a pseudopotential - if atomic energies are what you are interested in, use the ld1.x code.
Of course, plane waves are not really the best choice for Hartree Fock calculations (use a quantum chemistry codes) but if you are concerned about comparisons, maybe you could look at potential energy surfaces - e.g. the dissociation of a molecule, or the frequency normal modes - there you could compare Hartree-Fock within pw.x with other known results. Still, there could be better choices to get acqainted with the code - maybe browse, from the q-e website, the lectures/videos/tutorials of the 2009 Santa Barbara school. nicola steve ndengu? wrote: > Dear all, > > We have an enquiry about some results appearing in the output file of > the pw.x run. > > We are trying to perform computations on isolated atoms to try to get > a significance of the results given by the code. We have to recall > that we are new users of QE. And as far as we know it is not too much > indicated for such kind of computations but it is rather a first try > to get some understanding on the "behaviour" of the code. > > So the problem is that when performing the computations on He for > example we obtain the correct ground state energy up to the > Hartree-Fock limit. But when applied to other atoms (Li, Na, Be, C, > ...) the value obtained do not correspond at all to the known value. > > We thus have 2 questions: > > 1- Why is it that the level of refinement obtained is the Hartree-Fock > limit; we may have expected a better accuracy? Is it linked to the use > of pseudo-potentials? > 2- What can we do to recover the correct (up to the Hartree-Fock limit > at least) total energy for the other atoms? > > Sincerely Yours, > On behalf of the > Groupe de Structure et Dynamique des Atomes et Molecules > Laboratoire de Physique Fondamentale > D?partement de Physique > Universit? de Douala. > -- --------------------------------------------------------------------- Prof Nicola Marzari Department of Materials Science and Engineering 13-5066 MIT 77 Massachusetts Avenue Cambridge MA 02139-4307 USA tel 617.4522758 fax 2586534 marzari at mit.edu http://quasiamore.mit.edu