Hi,
As David said, (a,b,c) were fitted to reproduce at best the experimental
band gap of 23 solids. mBJ works quite well for many other solids not
included in this set, but there are also (many) cases where the mBJ
band gap is relatively far from experiment (still too small, but better
than
Dear WIEN2k community,
There is a strange thing with a crystal structure, I am playing with Gd
and H2O, so I put the following structure (I erased some lines);
P LATTICE,NONEQUIV.ATOMS: 4 1_P1
MODE OF CALC=RELA unit=ang
Pablo, if you read Fabien's original 2009 PRL on the mBJ the parameters (a.b.c)
were chosen to reproduce
Experimental band gaps. This does not call the work into question, the basic
method is on solid ground, but there
is a certain empirical fitting involved. It usually does reasonably well
Dear Fabien,
I think that there is a confusion here;
Semi empirical methods need parameters and one get, adjusting
parameters, good results
On the other hand DFT, in principle, does not need adjustable
parameters.
There are issues that need adjustable parameters,
here is optimized SnO2 structure
blebleble
P LATTICE,NONEQUIV.ATOMS: 2
136_P42/mnm
MODE OF CALC=RELA
unit=bohr
8.990462 8.990462 6.039906 90.00 90.00 90.00
ATOM -1: X=0. Y=0.
Z=0.
MULT= 2 ISPLIT=
8
-1: X=0.5000 Y=0.5000
Dear Qassim
The problem is in RMT of your structure so in the initialisation use 5% to
reduce it then it will works.
Good luck.
On Mar 4, 2016 10:23 AM, "Qasim Mahmood" wrote:
> Dear Wien2k users I want to optimize the the tetragonal structure of SnO2
> with space group
Dear Wien2k users I want to optimize the the tetragonal structure of SnO2
with space group 136_P42/mnm, the error of OPT_vol_-5.0
Stop error will occure at the start, please help me, What should i do to
overcome this error
Thanks and and regards
qasim
*Mr.Qasim Mahmood*
*Ph.D
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