On Nov 21, 2006, at 12:26 AM, Giuseppe Piero Brandino wrote: > Dear espresso user, > i have some questions about the pp.x program. > Asking the code to write the potential, for example > > plot_num=11=the V_bare + V_H potential, > > does it print the potential or the potential energy? > I know that it prints it in Rydberg, so an energy.
right > How do i get the potential? simply dividing by e right > or dividing by the total (ionic and electronic) charge density > in each point? this is a bit confusing to me. why would you divide by the local charge density? an energy divided by a charge density makes a potential times a volume, which is not what you expect, and furthermore I am not aware of any sensible use of the resulting quantity. > Something else, > is there a simple way to get the total charge density (electronic + > ionic) from pp.x? The ionic *pseudo*charge density is ill-defined when the pseudopotential is non local (as it usually the case). On the other hand, the physical (all-electron) valence+core charge density is not simply the sum of the valence pseudo-charge+ionic charge. What would be needed here is the sum of the all-electron ionic charge density + the valence charge density obtained from the reconstructed wave- functions. This is what is done the PAW formalism (see PE Bloechl, Phys. Rev. B 50, 17953 - 17979 (1994)). Work is in progress to implement PAW in Quantum Espresso. Meanwhile, there might be tools available to obtain a (more or less) quick-and-dirty recostruction of the charge, but others may be more appropriate than me to address this point. Stefano Baroni --- Stefano Baroni - SISSA & DEMOCRITOS National Simulation Center - Trieste [+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype) Please, if possible, don't send me MS Word or PowerPoint attachments Why? See: http://www.gnu.org/philosophy/no-word-attachments.html -------------- next part -------------- An HTML attachment was scrubbed... URL: /pipermail/attachments/20061121/5e1c178b/attachment.htm
