[Pw_forum] inconsistent quadrupolar coupling from gipaw calculation

Ary Junior aryjunior at gmail.com
Mon Oct 9 14:30:02 CEST 2017

Hi Jia,

I would start with Elk and I'm sending an example input file. More
information about essential convergence tests necessary to obtain some
initial results can be found at


Try starting with the default atomic species configuration files.


Ary Ferreira

FAPESP postdoctoral fellow
UFSCar - Brazil

On Mon, Oct 9, 2017 at 9:13 AM, Davide Ceresoli <davide.ceresoli at cnr.it>

> Dear Jia,
>      I have to admit that this is the first time that NMR/EFG results
> depend so much on the choice of the pseudopotential. I've calculated
> a bunch of minerals, both with NC and US pseudos, and results are
> in good agreement each other.
> I've tested several Co pseudos (NC, NC+semicore, PAW+semicore) on
> Co3O4 spinel and the EFG results span the entire real numbers range,
> both for Co and for O.
> Which one is correct? I don't know. I'm in favor of pseudopotentials
> with semicore states. They should be closer to all-electron.
> Do you have some reference with Co EFG calculated all-electron (wien2k,
> elk/exciting) on some simple system? If not, is there someone that
> could help us to setup a wien2k/elk calculation?
> Best regards,
>      Davide
> On 09/20/2017 06:50 PM, Jia Chen wrote:
> > Dear All,
> >
> > I am working on calculating nmr parameters with gipaw code. I have two
> settings:
> > one with norm-conserving gipaw pesudopotentials which has some semi-core
> states,
> > and the other with ultra-soft gipaw pseudopotentials. Electronic
> structure
> > eigenvalues from pwscf look similar, and chemical-shift are not far away
> from
> > each other. The issue is quadrupolar coupling, for Co, norm-conserving
> > calculation gives 0.5MHz and ultra-soft gives 1.5MHz. It seems to me a
> > significant discrepancy.  I don't know what caused the inconsistency,
> and which
> > one is more reliable. I appreciate any insight on this problem.
> >
> > One thing about norm-conserving calculation is that the code gives
> warming about
> > some orbitals has zero norm. I don't know if that could be of concern.
> >
> > Cheers
> > Jia
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum

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