[Wien] A confirmation is needed about mbj+so

[tran at theochem.tuwien.ac.at]

>I just finished some calculation with PBE/PBE+SO/mBJ+SO.
>I know that with mBJ we can not do force optimization.
>I know how to do force optimization with -SO

Forces with SO are not available in WIEN2k. Thus, optimization (min)
and SO can be used together only if SO is switched off on the
atoms which require an optimization of their positions.

>I have done PBE+mBJ calculation 
>save_lapw -d case
>initso_lapw and fixed position for some atoms and then 
>started min -j "run_lapw -ec xxx -cc xxx -fc x -i x"
>
>My first question:
>Is the above process is okay, can we do that? 
>From above method, my band gap is in the reasonable agreement with Experimental band gap (still optimization is going on).

Why are you executing initso_lapw since the option -so is not used?

>As we know the standard process for the mBJ is:
>1.init_mbj_lapw
>2. run_lapw -i 1 -NI
>3. save_lapw **
>4. init_mbj_lapw
>5. 0/1/2/3
>6. run_lapw .......
>
>So my second question: 
>If we do a general mBJ and then do -SO calculation after save_lapw in mBJ directory then -so will be assumed from the step 6 only. What would be the effect of step 2 "run_lapw -i 1 -NI" (that have
>been done in the case of mBJ and the -SO assumed from step 6).
>From above two question, I am not able to find a proper way to follow (mBJ)+(SO) or (mBJ+SO)

If your question is "Does it matter to use -so in step 2?", then
the answer is no.

>We can do in two ways if I understood it correctly,  first run an mBJ and then do scf with -SO is different then doing mBJ+SO in a single scf step. From one we can relax the structure while from two
>we can not.

The best is to do first a geometry optimization with a GGA like
PBE or PBEsol and without SO. Then, at this optimized geometry
(or at the experimental one if available) do the calculations that you
want (GGA+SO, mBJ, mBJ+SO).