[Wien] Initialization issue with core leak out of sphere And RMT Sums Greater than NN-DIST

[Peter Blaha]

You need rhombohedral coordinates (as the stucteditor says):
 > O1:   0.1295 0.1295 0.1295
 > Fe:   0.2141 0.2141 0.2141


Am 05.12.2011 11:24, schrieb Qiwen YAO:
> Dear all,
> I have been facing a few compounds that I am unable to do the initialization (using w2web) for the calculation.
>
> The problem is:
> I was facing both "core leak out of sphere, and  RMT Sums Greater than NN-DIST" at the same time.
>
> A recent example: I am trying to do an calculation initialization on the LuFe2O4  (R-3m group) crystal (cell parameters are from the Pearson's Crystal Data sheet 382676, a=b=0.3435nm, c=2.525nm, Alpha=Beta=90 degree, Theta=120 degree. Atomic positions:
> O1: 0  0  0.1295
> Fe:  0  0  0.2141
> O2: 0  0  0.2914
> Lu:  0  0  0
> ).
>
> Using the WIEN default RMT values and the default ENERGY to separate core and valence states (-6) , I was facing core electrons leak out of MT-sphere  message for all four atoms. So I go back to the<x start>  step and change the separation energy to the lowest possible value (-10 in this case) - if going any lower than -10, I will be seeing the error message after running<x start>, like these:
>
> forrtl: severe (24): end-of-file during read, unit -4, file stdin
> error: command   /home/wen/WIEN2K11/wien2k11install/lstart lstart.def   failed
>
> So, the natural step I took next is to increase the RMT values for the atoms correspondingly (according to each atom's core leak value). Then I am facing an another problem:  If I am to increase the RMT values too large, then in the<x nn>  step I will be seeing errors like
>
> ERROR !!!!!!!!!!!!!!!
>   RMT(  1)=0.53000 AND RMT(  1)=0.53000
>   SUMS TO 1.06000 GT NNN-DIST= 0.84061
>
> But if the RMT value is not increased enough then the core leaking message will still be there.
>
> So how would I solve such problems? I have been facing these for a few compounds - for example, the other compound I tried was BiAlO3 which would lead me to the same bottle-neck problem.
>
> Is there an automatic approaching way that I can take to get rid of both error message at the same time? For cases like these, if there is no practical solution to the initialization would that means the unit cell parameters were out of touch (reality)?
>
> Thank you for reading. I have been searching the archive for a solution but no luck.
>
> Kind regards,
> Wen
>
> **********************************************************
>
> Dr QiWen YAO
> JSPS Fellow
> Multifunctional Materials Group
> Optical and Electronic Materials Unit
> Environment and Energy Materials Research Division
>
> National Institute for Materials Science
>
> 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
> Phone: +81-29-851-3354, ext. no. 6482, Fax: +81-29-859-2501
>
> **********************************************************
>
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> Wien at zeus.theochem.tuwien.ac.at
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-- 

                                       P.Blaha
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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    WWW: http://info.tuwien.ac.at/theochem/
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