[Wien] Problems in convergence due to application of mBj potential

[Laurence Marks]

A Pratt greed of 0.5 or 0.2 will in general be very, very, very unstable.
0.03 may be too small.

After a few Pratt cycles let MSR1 take over with a greed of 0.1 if you want
to be conservative.

---------------------------
Professor Laurence Marks
Department of Materials Science and Engineering
Northwestern University
www.numis.northwestern.edu 1-847-491-3996
"Research is to see what everybody else has seen, and to think what nobody
else has thought"
Albert Szent-Gyorgi
 On Aug 22, 2012 8:34 AM, "Madhav Ghimire" <ghimire.mpg at gmail.com> wrote:

>  Dear Prof. Blaha,
> I have changed the PRATT with a mixing factor between 0.2-0.5 in case.inm
> not as small as you suggest. Thanks for this new information. I will try
> the suggested value and see what happens.
> Thanks
> Madhav
>
>
> On Wed, Aug 22, 2012 at 2:37 PM, Peter Blaha <pblaha at theochem.tuwien.ac.at
> > wrote:
>
>> It looks as if the mBJ calculation has completely crashed. "Constant"
>> tests are "unusual" and point to some other problem which you overlooked.
>>
>> restore_lapw gga_calc
>> runsp -i 1    (with GGA) (because you need good vsp and vresp files)
>> change to mBJ in case.in0; rm *.bro*
>> what did you set in case.inm ??? Choose a small (0.03) mixing with PRATT
>> for
>> the first couple of iterations
>> runsp      monitor :DIS from the beginning. It should not grow too large
>> and
>>            after about 10 cycles a slowly decreasing :DIS must be seen.
>> Then you
>>            can probably switch to MSR1a in case.inm
>>
>>
>> Am 22.08.2012 04:48, schrieb Madhav Ghimire:
>>
>>>  Dear wien users and developers,
>>>       I am working on some 3d TM oxides. With a normal scf cycle with or
>>> without inclusion of U value, I got good convergence in energy and charge.
>>> This oxide material is
>>> reported to have a bandgap of approx. 0.3 eV. In GGA, I do not observe
>>> any gap. In the meantime even with very high value of U, the bandgap do not
>>> open up. Because of this,
>>> I tried to implement mBj potential  (in order to find the bandgap) both
>>> with and without inclusion of U, but the energy and charge do not converge.
>>> Rather even for a large number of iteration (199), the energy and charge
>>> remains constant without convergence (shown below).
>>>
>>> For GGA without mBj the scf cycle smoothly converges as below:
>>> in cycle 22    ETEST: .0000236850000000   CTEST: .0038743
>>> in cycle 23    ETEST: .0000184300000000   CTEST: .0012996
>>> in cycle 24    ETEST: .0000174650000000   CTEST: .0006011
>>> in cycle 25    ETEST: .0000037600000000   CTEST: .0007451
>>> in cycle 26    ETEST: .0000016050000000   CTEST: .0001163
>>>
>>>  >   stop
>>>
>>> while  with mBj+GGA, energy and charge convergence remains constant
>>> above cycle 103 and could not converge as below:
>>> in cycle 193    ETEST: .2112103950000000   CTEST: 2.0591251
>>> in cycle 194    ETEST: .2112103950000000   CTEST: 2.0591251
>>> in cycle 195    ETEST: .2112103950000000   CTEST: 2.0591251
>>> in cycle 196    ETEST: .2112103950000000   CTEST: 2.0591251
>>> in cycle 197    ETEST: .2112103950000000   CTEST: 2.0591251
>>> in cycle 198    ETEST: .2112103950000000   CTEST: 2.0591251
>>> in cycle 199    ETEST: .2112103950000000   CTEST: 2.0591251
>>>
>>>  >   energy in SCF NOT CONVERGED
>>>
>>> Does anyone have experienced this type of problems. If so, please let me
>>> know how it can be converged. I followed all the steps as described in
>>> previous wien mail and
>>> userguid but could not solve.
>>> Your help to solve this issue will be higly appreciated.
>>> Thanks in advance
>>>
>>> Madhav Ghimire
>>>
>>> --
>>> MANA, National Institute for Materials Science (NIMS)
>>> 1-1 Namiki, Tsukuba, Ibaraki, Japan
>>> Phone: +81-29-851-3354 (ex.4115)
>>>
>>>
>>>
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>>>
>>> --
>>> MANA, National Institute for Materials Science (NIMS)
>>> 1-1 Namiki, Tsukuba, Ibaraki, Japan
>>> Phone: +81-29-851-3354 (ex.4115)
>>>
>>>
>>>
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>>>
>> --
>> ------------------------------**-----------
>> Peter Blaha
>> Inst. Materials Chemistry, TU Vienna
>> Getreidemarkt 9, A-1060 Vienna, Austria
>> Tel: +43-1-5880115671
>> Fax: +43-1-5880115698
>> email: pblaha at theochem.tuwien.ac.at
>> ------------------------------**-----------
>>
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>>
>
>
>
>  --
> MANA, National Institute for Materials Science (NIMS)
> 1-1 Namiki, Tsukuba, Ibaraki, Japan
> Phone: +81-29-851-3354 (ex.4115)
>
>
>
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