[Wien] Three questions

[Lukasz Plucinski]

Dear All,

Sorry for a longer email, but couple of things have accumulated. I have 
three questions, one on charge convergence, another one on setting the 
limits in case.inso and case.in1c to avoid large vector files, and a 
last one on some expert advice on how to converge FM+SOC calculations 
properly.


1. CHARGE CONVERGENCE: I know this has been discussed before, but it 
seems it didn't change in Wien2k_18. Here is a typical example of the 
charge convergence history of the last few iterations of FM+SOC 
(ferromagnetic + spin orbit coupling) calculation:

:ENERGY convergence:  0 0.0001 .0001320450000000
:CHARGE convergence:  0 0.001 .0027578
:ENERGY convergence:  1 0.0001 .0000497650000000
:CHARGE convergence:  0 0.001 .0050904
:ENERGY convergence:  1 0.0001 .0000557650000000
:CHARGE convergence:  0 0.001 .0004672
:ENERGY convergence:  1 0.0001 .0000220050000000
:CHARGE convergence:  1 0.001 -.0001786

Something strange happens with charge convergence, is this OK?


2. LIMITS in inso and in1c files: in order to avoid large vector files I 
am changing the energy limits in inso and in1c files for band structure 
calculations. SCF is done with default inso and in1c files, then I do 
save_lapw, then I edit case.inso and case.in1c files, and then I do 
FM+SOC band structure calculation:

#! /bin/bash
x lapw1 -band -up -p
x lapw1 -band -dn -p
x lapwso -up -p

I am using emin/emax -0.5 0.5 in both files (inso and in1c) without 
changing anything else, then I have bands from limited energy range. I 
just want to make sure that this procedure is fine.


3. FM+SOC convergence: I am doing FM+SOC calculations for different 
in-plane magnetization M directions in a 2D Fe(001) ferromagnetic layer. 
Actually an older Wien2k_14 version was not working well for this, 
results for generic M directions were really strange. Wien2k_18 seems 
much better, however, when starting things from the scratch (each M 
angle completely separate calculation) it seems that for some M angles 
the result is off, as if it didn't actually properly converge. I am 
using a fairly dense mesh for SCF (2000k, 25 25 3), and -ec 0.0001 -cc 
0.001.  Should I maybe try -fermit setting in init_lapw, and what would 
be a reasonable value? Do I always need to use instgen_lapw before 
init_lapw when starting a new case? Should I perhaps do each next M 
angle on top of a previously converged M angle (and save_lapw for each M 
angle)?


Best,
Lukasz