Dear Eduardo, thanks for your consideration on my problem,
Bests. Yavar -----Original Message----- From: Eduardo Ariel Menendez Proupin <[email protected]> To: pw_forum at pwscf.org Date: Mon, 9 Jul 2012 09:44:20 +0200 Subject: Re: [Pw_forum] HOMO,LUMO isosurface, USPP or NCPP? Dear Yavar USPP and NCPP are mathematical methods to approximate the solution of the same physical problem. Hence, there must be no physically different results, unless one of the pseudopotentials is faulty. Both types of pseudopotentials have cutoff radii, which are larger for NCPP than for USPP. The wavefunctions computed with any pseudopotential should be equal to the all-electron wavefunctions in the spatial region outside the spheres centered at each atom with spheres radii equal to the cutoff radii of the corresponding pseudopotential. Inside any sphere, the wavefunctions are different and are meaningless. To have the correct wavefunctions inside the spheres you have any of the following options a) all-electron calculations (with a different code,e.g. ADF, Gaussian, LMTO, etc), b) use a PP with a smaller cutoff radius (and larger ecutrho and ecutwfc), c) use PAW (projector augmented wave). sincerely yours Eduardo Menendez Proupin Departamento de Qu?mica Fisica Aplicada Facultad de Ciencias Universidad Aut?noma de Madrid 28049 Madrid, Spain Phone: +34 91 497 6706 Dear QE users. I want to plot HOMO, LUMO isosurfaces. what is the physical origin of difference between results from choosing USPP with NCPP? Thanks in advance. ------------------------------------------- Yavar Taghipour Azar PhD Student Physics Group, AEOI Tehran-Iran Email: ytaghipour at aeoi.org.ir Phone: +98 (0) 21 82064556 ----------------------------------------------------------- -- -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120710/69d1a228/attachment.htm
