[Pw_forum] HOMO,LUMO isosurface, USPP or NCPP?

[Yavar Taghipour Azar]

Dear Eduardo,

thanks for your consideration on my problem,

Bests.

Yavar


-----Original Message-----
From: Eduardo Ariel Menendez Proupin <eariel99 at gmail.com>
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 Química Fisica Aplicada
Facultad de Ciencias
Universidad Autónoma 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
-----------------------------------------------------------


 



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