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["Wu Rongqin" <g0203654@nus.edu.sg>]

Good. As I used the Teter-type extended norm-conserving pp, the results are 
much better. 
From this I see that how important the configuration of a pp is. If one can 
teach me how to use fhi98pp to generation the pps. I promise to generate and 
test all the pps through the periodical table!
Anyone like to teach me?
Rongqin 

-----Original Message-----
From: Masayoshi Mikami [mailto:mmikami@yk.rim.or.jp] 
Sent: 2004年7月15日 21:54
To: forum@abinit.org
Subject: Re: [abinit-forum] help about pp

Hello colleagues,

May I add comment from my experience with Ti-oxide ?
When I tried calculation of TiO2 (anatase), 
I experienced the similar situation with Troullier-Martins (TM)
Ti potential with 3s/3p as core states; even with 
non-linear core-correction, the situation was not improved.

But I obtained a good geometry with TM Ti potential 
with 3s/3p (and 3d, 4s) as valence states. The Teter-type 
extended norm-conserving PP also gave a good geometry, too.
(the slight difference was observed in total energy difference
 between rutile phase and anatase phase)
The summary was reported by ourselves:
M. Mikami et al., Jpn. J. Appl. Phys. Vol.39 (2000) L847-L850
http://jjap.ipap.jp/link?JJAP/39/L847/
(NB: I did not report my bad case (Ti-3s/3p as core) in the paper ...)

As you see in the Table in the above paper, 
some papers on rutile calculation report larger lattice constants 
than the experimental data. The authors in the papers employed 
Ti PP with 3s/3p as core states.

As mentioned in ~ABINIT/Infos/Psp_infos/psp1.data,
"BaTiO3 :
...(snip)...
NOTE : the bad lattice parameter wrt experiment can be attributed to the lack
of semi-core 3s and 3p state for the Titanium pseudopotential. Semicore
states are important in this case, because the strongly electronegative
oxygen pump the electrons of Ti ..."

The same logic may hold true for Zr-oxides etc.

Good continuation,
Masayoshi

From: Johann Bouchet <bouchet@pcpm.ucl.ac.be>
Subject: Re: [abinit-forum] help about pp
Date: Thu, 15 Jul 2004 15:30:24 +0200
Message-ID: <40F686F0.2090300@pcpm.ucl.ac.be>

> Dear Wu,
> 
> I'm currently using the Teter "extended norm-conserving" pseudopotential 
> <http://www.abinit.org/ABINIT/Psps/LDA_EX/lda.html> for Zr, the volume 
> we found for ZrO2 is slightly below the experimental one. Keep faith.
> 
> Johann
> 
> > Dear all,
> >
> > As I tested the  tm Zr pp downloaded from the abinti website and found 
> > that the calculated lattices are 10% greater than experimental ones. 
> > So any body can generate one for me?
> >
> > In my test, I did not take the spin polarization into account.
> >
> > I am desperate.
> >
> > Rongqin wu
> >