[Pw_forum] Total energy does not converge with ecut

[Eyvaz Isaev]

Timothy,  

--- On Wed, 11/12/08, Timothy Mason <thmason24 at yahoo.com> wrote:
> 
> sadly there is no typo.  

Then quite strange how could you proceed your calculations. readpp.f90 should stop pw.x

> Those are indeed the PsPs I was using(hopefully I've
> havn't exposed myself as hopeless). I have
> witnessed that sometimes the calculations stop which seems
> to be structure dependent.

If you are absolutely sure that the structure is correct, this one actually might be a reason for doubts about a PsP quality (transferability).
Otherwise, check your structure via XCrysDen.

> is there a reference regarding guidelines for selecting
> Pseudopotentials?

I do not think so. It will be not so democratic.
This should be only your choice, and depends on your experience. 
The gold rule is the use of PsPs with the same XC-functional, at the same time you can mix different type of PsPs (normconserving, ultrasoft, and, hopefully, PAW now).

> in general its a bad ideal to mixmatch types of
> pseudopotentials?
> 

Presumably, mismatch, but not mixmatch. In general, and in particular, it is a bad idea with respect to XC-type only, indeed. Otherwise, see above.

> thanks a lot for your help.

Welcome.

Bests,
Eyvaz.
> 
> 
> --- On Tue, 11/11/08, Eyvaz Isaev
> <eyvaz_isaev at yahoo.com> wrote:
> From: Eyvaz Isaev <eyvaz_isaev at yahoo.com>
> Subject: Re: [Pw_forum] Total energy does not coverge with
> ecut
> To: thmason24 at yahoo.com
> Date: Tuesday, November 11, 2008, 2:51 PM
> 
> Hi Timothy,
> 
> 
> --On Tue, 11/11/08, Timothy Mason
> <thmason24 at yahoo.com> wrote:
> > Subject: Re: [Pw_forum] Total energy does not coverge
> with ecut
> > 
> > I'm now using 
> > 
> >  Li.pz-n-vbc.UPF
> >  N.pbe-rrkjus.UPF
> >  H.pbe-rrkjus.UPF
> > 
> > and they seem to converge nicely.
> > 
> 
> Quite strange. The program had to be stopped, because you
> mentioned PsPs with
> different XC-functionals. 
> 
> I would suggest there is a typos with Li.pz.....
> If so, and you meant Li.pbe.... then it is OK.
> Nevertheless, nobody can tell
> you which PsP is better for your system until you perform a
> test for yourself. 
> 
> Good Espresso time!
> 
> bests,
> Eyvaz. 
> 
> > is there problem with the ones I was using?   here
> they
> > are for reference
> > 
> > Li 6.941000 Li.pbe-n-van.UPF
> > N 14.006740 N.pbe-van_ak.UPF
> > H 1.007940 H.pbe-van_ak.UPF
> > 
> > I'm not sure of the best way to select them from
> the
> > website.
> > 
> > thanks for the help.
> > 
> > 
> > 
> > 
> > 
> > 
> -------------------------------------------------------------------
> Prof. Eyvaz Isaev, 
> Theoretical Physics Department, Moscow State Institute of
> Steel & Alloys,
> Russia, 
> Department of Physics, Chemistry, and Biology (IFM),
> Linkoping University,
> Sweden 
> Condensed Matter Theory Group, Uppsala University, Sweden 
> Eyvaz.Isaev at fysik.uu.se, isaev at ifm.liu.se,
> eyvaz_isaev at yahoo.com