[Wien] FCORE not converged at RMT warnings

[Peter Blaha]

There is a component of the force calculated as an integral over the 
atomic spheres of rho_core * V_1x.
When the core charge is "zero" at RMT, this integral is considered as 
"converged".
I've added a test integating this to RMT or RMT-(1 radial mesh point)
and if the difference is larger than a certain threshold, it prints a 
warning. (see also case.outputc file.

In your case it concerns the Hf sphere and the estimated error (actually 
the difference mentioned above, so the error could be a bit larger) is 
0.24 mRy/bohr.

If you are just using the forces for structure optimization (with 2.0 
mRy/bohr in case.inM), you can probably ignore this inaccuracy.

For phonons you better should not ignore it.

At the moment possible solutions are either to specify a lower -ecore 
and include more semi-core states as valence, or increase RMT.

PS: The reason for seeing it in mBJ and not in LDA is probably because 
the nonspherical potential V_1x becomes larger with mBJ. On the other 
hand, you should not optimize positions anyway with mBJ, so this is 
irrelevant for gaps, .....


On 09/25/2014 10:32 AM, Pavel Ondracka wrote:
> Dear Wien2k mailing list,
>
> after upgrade to Wien2k_14 I'm seeing this warning:
>
> FCORE for atom   1 not converged at RMT. Estimated inaccuracy:  0.2417
> mRy/bohr
>
> This is a monoclinic HfO2 cell, atom 1 is Hf atom (struct file
> attached). I'm using the mBJ potential and I don't see this warning
> during the LDA run before I initialize mBJ, only with mBJ.
>
> Is this a problem? What parameters should I tweak to get rid of this?
>
> Best regards
> Pavel Ondračka
>
>
>
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> SEARCH the MAILING-LIST at:  http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>

-- 

                                       P.Blaha
--------------------------------------------------------------------------
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
Email: blaha at theochem.tuwien.ac.at    WIEN2k: http://www.wien2k.at
WWW:   http://www.imc.tuwien.ac.at/staff/tc_group_e.php
--------------------------------------------------------------------------