[Wien] Regarding PBE Calculation of Al2O3

[Peter Blaha]

Your structure is wrong.

Al2O3 has a rhombohedral lattice. Please read in the UG (struct file) 
how to specify such a structure. (also w2web gives you hints about that):

You need to give the hexagonal unit cell (as you did), but the positions 
of the atoms in rhombohedral coordinates (you did not do that).

Conversion is possible by using   hex2rhomb


On 07/05/2017 08:26 AM, apande at iitk.ac.in wrote:
> Dear Wien2k users
>
> I am trying to do PBE calculations for Al2O3 by following steps
>
> 1. Genrate the structure
> Al2O3 Space Group :(167)
>       Lattice Parameters: a=4.757 b=4.757 c=12.988
>       alpha=90=beta gamma=120
>       Positions : Al(0,0,0.35218)  O(0.30625,0,1/4)
>
> Reduce RMT by 0% : This reduces RMT to 1.09 for both atoms
> Save file and Cleanup
>
> 2. Initialize Calculation
>
> xnn : nn bondlength factor 2
>       executed , continue with LAPW
>
> now the error appears that says:
>
> ERROR : Your sphere sizes are unphysically small !!!!
> Most likely your structure is WRONG and will lead to crash later. You
> should probably stop and recheck your struct file.
>
>
> The problem is if the RMT is increased by editing struct file manually the
> xnn step gives an ERROR where the "sums to" length is more than the "GT
> NNN-DIST"length
>
> And if the RMT is not changed there is the sphere size error stated earlier.
>
> Please help
>
> With Regards
> Aditya Pande
>
> _______________________________________________
> 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/TC_Blaha
--------------------------------------------------------------------------