Dear users and developers, I have two related questions about what would be more meaningful to extract from a SCF calculation with DFT in Quantum Espresso as far as the *mean internal potential* is concerned.
This quantity, in electron microscopy experiments, is linearly related (at least in first approx) to the response of the electron beam passing through a sample. In developing the theory of the response one uses the single particle static electic potential felt by the electrons given, in turn, by the solution of the Poisson equation for the total charge existing in the interior of the sample. Now: a. I wonder if the the DFT setting one has to use the Kohn-Sham potential (as "best" single body potential in the many-body problem) or only the contributions coming from ions + Hartree term coming from the electronic charge. In a series of papers of the '90s o 2000s I have seen that they use the second option. The rationale would be that the electrons from the beam at high energy are not really a part of the sample and are not correlated with the ones of the interior. Would you agree? b. Again in those papers they choose *linear augumented plane wave full potential*. Why should one use PAW? In which sense full potentials? Aren't Pseudos sufficient? Thanks a lot for your time. -- Cristian Degli Esposti Boschi CNR-IMM, Sezione di Bologna, via Gobetti, 101, 40129, Bologna, Italia tel. ++39 051 6399152, fax ++39 051 6399216 email: degliesposti -AT- bo.imm.cnr.it web: www.bo.imm.cnr.it/site/staff/personal_pages/degliesposti/ _______________________________________________ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum