Hi,
MSR1 and PRATT (not PRRAT) should obviously lead to the same results
as long as you let the calculations run until they are sufficiently
well converged. By default a calculation stops after 40 iterations
even if the convergence criteria are not reached. Execute run_lapw with
option "-i 100" to increase to 100 for instance.
Usually, I start with MSR1. If the calculation
does not seem to converge with MSR1 (infinite oscillations or diverge),
I stop the calculation. Then, I restart the calculation with
PRATT with a very small mixing factor like 0.05 and regenerate
case.clmsum with dstart or from previous PBE calculation.
Then, if the calculation seems to converge, I switch back to default
parameters in case.inm to reach convergence a little bit faster.
F. Tran
On Wed, 16 Dec 2015, shima pourrad wrote:
Dear F.Tran
I appreciate a lot because of your explanation. I ran the calculations with
-ec 0.00001 convergence criteria. But unfortunately I
found that I made a bad mistake : for the second calculation I forgot to change
the mixing scheme to PRRAT , and it ran with the
default mixing scheme which is MSR1. And this mistake causes two different
results.(When I corrected mixing scheme , both
calculations gave me the same results ). I apologize because of this
carelessness.
So I have another question, which of the two mixing schemes gives me reliable
results? I mean, is it possible my first calculation
(with PRRAT and mixing factor=0.2) converged to the ghost band?? In user guide
it was written that: in most cases it is possible
to switch back to MSR1 after some initial scf-cycles. Can we use MSR1 from the
first of the calculation? What kind of mixing scheme
we can use for the mbj calculations?
Thanks a lot.
Shima M.pourrad
On Mon, Dec 14, 2015 at 7:39 PM, <t...@theochem.tuwien.ac.at> wrote:
For the moment, I suspect that your calculations are not very well
converged. Did you run the calculations with good energy and charge
convergence criteria? If not, run the two calculations with
-ec 0.0001 -cc 0.0001
which is fairly good criteria. Then, maybe the two calculations
give same results.
On Mon, 14 Dec 2015, shima pourrad wrote:
Hi
Thanks for your prompt answer.
Yes, for the first calculation with “ EX_GRR VX_GRR” I have :
Case.in0 :
TOT XC_MBJ (XC_LDA,XC_PBESOL,XC_WC,XC_MBJ,XC_REVTPSS)
R2V IFFT (R2V)
120 120 120 1.00 1 min IFFT-parameters, enhancement factor,
iprint
And case.in0_grr :
TOT EX_GRR VX_GRR (XC_LDA,XC_PBESOL,XC_WC,XC_MBJ,XC_REVTPSS)
R2V IFFT (R2V)
120 120 120 1.00 1 min IFFT-parameters, enhancement factor,
iprint
This calculation give me these results by Analysis :
--- ENE -----------
in 1 files:
case.scf::ENE : *WARNING** TOTAL ENERGY IN Ry =
-79386.93188247
--- FER -----------
in 1 files:
case.scf::FER : F E R M I - ENERGY(TETRAH.M.)= 0.4117108915
--- GAP -----------
in 1 files:
case.scf::GAP : 0.0564 Ry = 0.767 eV (provided you have a
proper k-mesh)
For the second calculation with “ EX_GRR EC_NONE VX_GRR VC_NONE” I
have:
Case.in0 :
TOT XC_MBJ ( (XC_LDA,XC_PBESOL,XC_WC,XC_MBJ,XC_REVTPSS)
R2V IFFT (R2V)
120 120 120 1.00 1 min IFFT-parameters, enhancement factor,
iprint
And case.in0_grr :
TOT EX_GRR EC_NONE VX_GRR VC_NONE (
(XC_LDA,XC_PBESOL,XC_WC,XC_MBJ,XC_REVTPSS)
R2V IFFT (R2V)
120 120 120 1.00 1 min IFFT-parameters, enhancement factor,
iprint
And its results :
--- ENE -----------
in 1 files:
case.scf::ENE : *WARNING** TOTAL ENERGY IN Ry =
-79386.93585459
--- FER -----------
in 1 files:
case.scf::FER : F E R M I - ENERGY(TETRAH.M.)= 0.4269866858
--- GAP -----------
in 1 files:
case.scf::GAP : 0.0423 Ry = 0.575 eV (provided you have a
proper k-mesh)
what is your opinion?
Sincerely
Shima M.Pourrad
On Mon, Dec 14, 2015 at 6:11 PM, <t...@theochem.tuwien.ac.at> wrote:
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
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