[Wien] A question about the Rkm

[Peter Blaha]

I do not know many compounds, for which an RMT=1.2 bohr for H makes any 
sense (maybe LiH). Use setrmt and follow the suggestion. Usually, H 
spheres of CH or OH bonds should be less than 0.6 bohr. Experimental 
H-position are often very unreliable.

How many k-points ? Often 1 k-point is enough for 50+ atoms (at least at 
the beginning), in particular when you ahve an insulator.

Otherwise, follow the suggestions of L.Marks about parallelization.

Am 08.01.2016 um 07:28 schrieb Hu, Wenhao:
> Hi, all:
>
> I have some confusions on the Rkm in calculations with 50+ atoms. In my wien2k, the NATMAX and NUME are set to 15000 and 1700. With the highest NE and NAT, the Rkmax can only be as large as 2.05, which is much lower than the suggested value in FAQ page of WIEN2K (the smallest atom in my case is a H atom with radius of 1.2). By checking the :RKM flag in case.scf, I have the following information:
>
> :RKM  : MATRIX SIZE 11292LOs: 979  RKM= 2.05  WEIGHT= 1.00  PGR:
>
> With such a matrix size, the single cycle can take as long as two and half hours. Although I can increase the NATMAX and NUME to raise Rkmax, the calculation will be way slower, which will make the optimization calculation almost impossible. Before making convergence test on Rkmax, can anyone tell me whether such a Rkmax is a reasonable value?
>
> If any further information is needed, please let me know. Thanks in advance.
>
> Best,
> Wenhao
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
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