The ABINIT Users Mailing List ( CLOSED )

[Mozhgan Amini <mozhganamini@yahoo.com>]

Dear Josef,

I have done the calculation for this system first with 12electron paw dataset for Cd:  2.5314669846  : r_cut(PAW)
then I wanted to also try it with 20electron dataset: (This Gives Error!!)
2.0100000000     : r_cut(SPH)

as you see, the radius for the second one is smaller, so how can I have overlapping in this case!??

Best Regards,
Mozhgan


 

--- On Fri, 2/5/10, Josef Zwanziger <jzwanzig@gmail.com> wrote:

From: Josef Zwanziger <jzwanzig@gmail.com>
Subject: Re: [abinit-forum] PAW overlapping!
To: forum@abinit.org
Date: Friday, February 5, 2010, 6:21 PM

The PAW datasets are defined by spheres around each atom in real
space. The PAW formalism takes as an important given that the spheres
of neighbouring atoms do not overlap. The pawovlp variable controls
how much overlap Abinit will tolerate, but it is very dangerous to
allow any overlap at all. The fix to this problem is to use PAW
datasets with radii small enough that they don't overlap. Check the
PAW sets you are using--the 12th line of the file will say something
like "2.20 ... : r_cut (PAW)", and the number 2.20 is the radius (in
Bohrs) of the sphere for that atom. For your input structure you know
how close the closest atoms are, so you can check this way whether
your PAW sets have too big radii.

If the PAW sets have too big radii, then the only fix is to make new
datasets with smaller cut-offs. We have an extensive and helpful part
of the web site that explains how to do this, let me know if you have
questions about it.


Josef W. Zwanziger
Professor of Chemistry
Canada Research Chair in NMR Studies of Materials
Director, Nuclear Magnetic Resonance Research Resource (NMR-3)
Dalhousie University
Halifax, NS B3H 4J3 Canada
tel: +1 (902) 494-1960
fax: +1 (902) 494-1867
web: http://jwz.chem.dal.ca
jzwanzig@gmail.com, jzwanzig@dal.ca



On Fri, Feb 5, 2010 at 10:43 AM,  <mozhganamini@yahoo.com> wrote:
> Dear Abinit users,
>
> I've done relaxation of atomic positions for CdO with impurity atom,
> first I did it with 12e paw dataset for Cd and
> then I tried 20e paw dataset, But this time I had overlapping and program
> stops!
>
> (I should also say that, in paw dataset cutoff radius of 20e is smaller than
> 12e!)
>
> do you know what can be the reason and what should I do!?
>
> Best Regards,
> Mozhgan
>