[Wien] 'LOPW' - Plane waves exhausted

[Florian Meirer]

Dear Wien2k users,

I am having a problem with a supercell calculation:

- I am running wien version 11.1 (Release 14/6/2011) on a Intel XEON
X5650 @ 2.67Ghz (2 Processors), 24Gb RAM with operating system Ubuntu
64bit, fortran compiler ifort 11.1.073 and math libraries R_LIB
(LAPACK+BLAS): -lmkl_lapack -lmkl_intel_lp64 -lmkl_intel_thread
-lmkl_core -openmp -lpthread -lguide

- The purpose of my calculations is to perform a structural relaxation
(PORT) around an impurity (Sn dopant in Germanium)
- I successfully performed the same calculation for an As impurity in
Silicon and achieved good agreement with literature and experimental
data (XANES).

- I started with the struct:
----------------------
Germanium
F   LATTICE,NONEQUIV.ATOMS:  1 227 Fd-3m
MODE OF CALC=RELA unit=ang
 10.691735 10.691735 10.691735 90.000000 90.000000 90.000000
ATOM   1: X=0.12500000 Y=0.12500000 Z=0.12500000
          MULT= 2          ISPLIT= 2
       1: X=0.87500000 Y=0.37500000 Z=0.37500000
Ge1        NPT=  781  R0=0.00005000 RMT=    2.2300   Z: 32.0
----------------------
then created a supercell (2x2x2) and replaced one Ge by Sn (final
.struct file attached).
The parameters I used for testing:
R0's were adjusted to 0.00005 for Ge and to 0.00001 for Sn (as
recommended: http://www.wien2k.at/reg_user/faq/r0.html);
Default settings for the rest:
RKmax=7, k=200, PBE-GGA, -6.0Ry, not spin-polarized
SCF: run_lapw -p -it -ec 0.0001 -fc 1 -cc 0.001 -NI
I am running 10 parallel jobs and lapw1_10.error returns:
Error in LAPW1
 'LOPW' - Plane waves exhausted

- I have already consulted the mailing list and tried to following:
1) replaced SRC_lapw1/lopw.f with the one provided here:
http://zeus.theochem.tuwien.ac.at/pipermail/wien/2011-August/015142.html
and recompiled in folder.
2) increased RKmax (also suggested in the mailing list somewhere)
3) changed number of parallel jobs
4) broke symmetry of struct file completely; i.e. each atom labeled
individually, P-type struct -> LOPW does not crash but a) the
calculation takes forever and b) the forces did not converge
5) finally, as it seems related to the k-points, I reduced the number
of k-points to 4 (k=100) and LOPW does not crash ... however, I am not
happy using only 4 k-points... this seems too low?
6) I read that: "This is usually due to an error in your struct file.
(Specifying the same atom twice,....)"
(http://www.wien2k.at/reg_user/mailing_list/wien-digest.archive/summary_2001),
but I cannot find my mistake...

- The thing that puzzles me is the fact that the same calculation
worked perfectly fine for an As impurity in Si (same structure, same
parameters ...)
I am probably missing something but cannot find my mistake.

Many thanks for any suggestions!
Best regards,
Florian Meirer

------------------------------------------------------------
Florian Meirer (PhD)
MiNALab - Center for Materials and Microsystems - irst
FBK - Fondazione Bruno Kessler
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