[Pw_forum] Pw_forum Digest, Vol 48, Issue 71

[Deyu Lu]

Thank Nicola and Paolo for the reply. I did some further tests.
The oxygen psp (both fhi form and input file) was downloaded from http://www.abinit.org/downloads/psp-links/gga_fhi. In the previous
test, I converted fhi to UPF directly. Following Nicola's suggestion,
I regenerated the cpi file with 08-O.GGA.ini using fhi98pp. The output
(O.cpi) is converted to UPF using fhi2upf. The mesh of the new psp (O.cpi.UPF) starts from 7.81250000000E-04, the same as 08-O.PBE.fhi.UPF, but is slightly different from 7.81252980657E-04 in 
O.pbe-mt.UPF. The resulting lattice constant is 4.633 A, consistent with what I found before.

In the attachment, I include the input/output using O.pbe-mt.UPF (2.d) and O.cpi.UPF (10.d).

Best
Deyu



> Message: 1
> Date: Tue, 28 Jun 2011 09:31:17 +0200
> From: Paolo Giannozzi <giannozz at democritos.it>
> Subject: Re: [Pw_forum] oxygen pseudopotential in tio2
> To: PWSCF Forum <pw_forum at pwscf.org>
> Message-ID: <2A8AABA7-2A96-4B25-93B5-21C3E1FC86D1 at democritos.it>
> Content-Type: text/plain; charset=US-ASCII; delsp=yes;
> format=flowed
> 
> 
> On Jun 28, 2011, at 3:27 , Deyu Lu wrote:
> 
> > There seems to be a bug in the <PP_HEADER>
> section of O.pbe-mt.UPF,
> > where Max angular momentum component is set to 1
> instead of 2.
> 
> this should be correct: the projectors have a maximum
> angular  
> componente l=1,
> while l=2 is in the local part only
> 
> > In the end, I was quite confused about the fact that a
> very small  
> > change in
> > the mesh (<5d-3 max at 80 a.u.) can cause a
> difference in the  
> > lattice constant by 1%.
> 
> interesting...
> 
> P.
> ---
> Paolo Giannozzi, Dept of
> Chemistry&Physics&Environment,
> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
> 
> 
> 
> 
> 
> 
> ------------------------------
> 
> Message: 2
> Date: Tue, 28 Jun 2011 08:46:43 +0100
> From: Nicola Marzari <nicola.marzari at materials.ox.ac.uk>
> Subject: Re: [Pw_forum] oxygen pseudopotential in tio2
> To: PWSCF Forum <pw_forum at pwscf.org>
> Cc: Deyu Lu <deyulu at yahoo.com>
> Message-ID: <4E0986E3.9000605 at materials.ox.ac.uk>
> Content-Type: text/plain; charset=ISO-8859-1;
> format=flowed
> 
> 
> 
> Thanks Deyu Lu for this very careful analysis.
> 
> It looks like the two pseudos are coming from the same
> source
> (the FHI fhi98pp repository), but 08-O.PBE.fhi.UPF as a UPF
> conversion
> of the abinit PSP library, while O.pbe-mt.UPF as a direct
> conversion
> from the fhi98pp output.
> 
> My first guess is that either
> 
> 1) the fhi to UPF conversion for O.pbe-mt.UPF was not done
> properly
> 
> or
> 
> 2) the fhi to UPF converter messes up the start of the
> radial mesh.
> 
> Would you be so kind to test 1) - i.e. download/compile the
> fhi code,
> obtain the TM pseudopotential with their parameters,
> convert it to
> UPF, and test?
> 
> If it comes out right, either the conversion was not done
> properly or 
> the converter has been fixed. If it comes out wrong, there
> is a problem
> with the converter.
> 
> Very much appreciated,
> 
>            
> nicola
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