[Wien] question about wien2k v 10.1 R0 too big warning message

[Peter Blaha]

a) Small R0 values were not trapped in earlier WIEN2k versions. Thus a lack of these
warnings does not guarantee that there's no problem.
b) If RO is only a little bit too small, it may not affect some/all results.
    Most affected are the forces, while a DOS,.. should be ok anyway.
c) I don't believe that w2web generates a too large R0.
    Probably you used the CoO-struct from the example directory, which has this large R0.
    Once you have such R0 value, w2web will NOT change it. w2web generates only for a
    new structure the correct Z, R0, but never changes existing data.

Am 11.03.2011 18:44, schrieb Jing-Han Chen:
> Dear Sir/Ma'am
>
> I installed the WIEN2k v 10.1 without any error. After installing, I tried to init_lapw the struct file in the folder example_struct_files/coo.struct. I got following the
> WARNING, even though the R0 value corresponds to the one also suggested by w2web.
>
> ----------------------------------------------------------------------------------------
>  >   lstart    (13:45:12)   SELECT XCPOT:
>    recommended: 13: PBE-GGA (Perdew-Burke-Ernzerhof 96)
>                  5: LSDA
>                 11: WC-GGA (Wu-Cohen 2006)
>                 19: PBEsol-GGA (Perdew etal. 2008)
> 13
>    SELECT ENERGY to separate core and valence states:
>    recommended: -6.0 Ry (check how much core charge leaks out of MT-sphere)
>    ALTERNATIVELY: specify charge localization
>    (between 0.97 and 1.0) to select core state
> -6
>
> WARNING: R0 for atom   -1 Z= 27.00 too big
>
>
> WARNING: R0 for atom   -2 Z= 27.00 too big
>
>
> WARNING: R0 for atom   -3 Z=  8.00 too big
>
> LSTART ENDS
> 0.240u 0.050s 0:04.44 6.5%    0+0k 0+776io 0pf+0w
> WARNING: R0 for atom   -1 Z= 27.00 too big
> WARNING: R0 for atom   -2 Z= 27.00 too big
> WARNING: R0 for atom   -3 Z=  8.00 too big
>         check coo.outputst how much core charge leaks out
>         if you continue, file .lcore will be created and the scf-cycle
>         will be run with core-density superposition
>         alternatively you can rerun lstart with a smaller ECORE
>
> ---------------------------------------------------------------------------------------------------
>
> As stated above, I tried to create this struct file by using w2web and the R0 value is the same as the one automatically generated in that case. However, I get the same
> WARNING message. After changing to smaller R0, I can init_lapw the input file without any WARNING. I never get this message/WARNING by WIEN2k v 8.2 while I use the same
> input file, since we still have v8.2 installed on one of our other machines. Although the calculation appears to proceed normally in v 10.1, we are surprised at this
> warning and are concerned that it may indicate something wrong in our setup. Is it because I did something wrong during compiling? Can I continue to use R0 given by w2web
> even if I get this WARNING, or does anyone know how to fix this problem?
>
>
> Thanks in advance
>
> --
> Jing-Han Chen
> Graduate Student
> Department of Physics
> Texas A&M University
> 4242 TAMU
> College Station TX  77843-4242
> jhchen at tamu.edu <mailto:jhchen at tamu.edu>
>
>
>
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-- 
-----------------------------------------
Peter Blaha
Inst. Materials Chemistry, TU Vienna
Getreidemarkt 9, A-1060 Vienna, Austria
Tel: +43-1-5880115671
Fax: +43-1-5880115698
email: pblaha at theochem.tuwien.ac.at
-----------------------------------------