[Wien] MBJ, case.in0_grr

[tran at theochem.tuwien.ac.at]

Hi,

"XC_MBJ" in the 1st line of case.in0 indicates that the mBJ method
will be used. For mBJ, it is necessary to have also the file case.in0_grr
such that the average of grad(rho)/rho in the unit cell
[used for Eq. (3) in PRL 102, 226401 (2009)] is calculated.

According to a test that I've just made it does not matter which one
of these two is specified in case.in0_grr:
"EX_GRR EC_NONE VX_GRR VC_NONE"
"EX_GRR VX_GRR"

So, I don't understand why you got two different results.
Can you show us the input files case.in0 and case.in0_grr
that you used for the two calculations?

F. Tran

On Mon, 14 Dec 2015, shima pourrad wrote:

> 
> Dear P.Blaha and F.Tran and Wien2k Users
> 
> I am running wien version14.2 .The purpose of my calculations is to get accurate gap and band structure. Hence I am performing MBJ calculations with the parameters special to semiconductors.
> 
> I would like to ask how we should edit case.in0_grr for a mbj calculation in wien2k14.2 ?
> 
> I read the user guide and checked the mailing list before, I didn’t find any obvious instruction.
> 
> In user guide, it was written that: when you perform init_mbj_lapw for the second time, some steps must do automatically:
>
>  * 
>
>     edit case.in0 and change the functional to option XC_MBJ. (ok this step is done).
>
>  * 
>
>      cp case.in0 case.in0_grr and choose EX_GRR VX_GRR in case.in0_grr.
> 
> But this step, when I open the case.in0_grr to check that, at first line, it was written that: EX_GRR EC_NONE VX_GRR VC_NONE. Is it a correct edition? Should I remove “EC_NONE VC_NONE” from the first line?
> 
> I think “EX_GRR EC_NONE VX_GRR VC_NONE” means that correlation energy and potential are ignored! But “EX_GRR VX_GRR” alone, means there is a kind of correlation energy and potential as a default for usual mbj calculation. Did I realize correctly??
> 
> You answered the question about the use of the PBE instead of LDA for the energy before: http://www.mail-archive.com/wien%40zeus.theochem.tuwien.ac.at/msg13395.html
> 
> And it is stated that how we must change case.in0 .
> 
> But there is no instruction for case.in0_grr. What should be done for this issue?
> 
> (What kind of edition is correct for case.in0_grr? “EX_GRR VX_GRR”? Or “ EX_GRR EC_NONE VX_GRR VC_NONE”?? I performed both of them for one structure, and got very different result: different Gaps, different total energies and different Fermi-energies!!! )
> 
> Please help me.
> 
> Sincerely
> 
> Shima M.Pourrad
> 
> PhD student of physics in condensed matter
> 
> Science and Research Branch
> Islamic Azad University
> 
>