Dear Prof, Peter,
I apologize for my last reminder for the query on overestimated band gap by
PBE
<http://www.mail-archive.com/search?l=wien@zeus.theochem.tuwien.ac.at&q=subject:%22Re%5C%3A+%5C%5BWien%5C%5D+overestimated+band+gap+by+PBE%22&o=newest>
It is nicely explained by Prof. Xavier and Gavin.

Your email was also in spam, so I just checked it.

My rmt for both cases are same (I did a common initialization for both
cases and then ran two scf with different scf criteria.
I hope, it is now much clear for you to make any comments.

Bhamu


On Wed, Nov 23, 2016 at 7:10 AM, Dr. K. C. Bhamu <kcbham...@gmail.com>
wrote:

> Dear Prof. Xavier
>
> I could not see your reply (it was in spam).
>
> I got the point.
>
> Thank you very much Prof. Xavier and Gavin
>
> Cheers!!!
>
>
> Bhamu
>
>
> On Wed, Nov 23, 2016 at 4:15 AM, Dr. K. C. Bhamu <kcbham...@gmail.com>
> wrote:
>
>> Dear Prof Peter,
>>
>> Please comment of my query when you get time:This is in the queue on my
>> previous query regarding CH3NH3PbI3:
>>
>>>
>>> I used two strategy and got different results:
>>>
>>>
>>> The experimental band gap is 1.67 eV for orthorhombic lead halide
>>> perovskite.
>>>
>>> I ran two cases (with PBE);
>>> 1. with 1000 k, div: ( 11  7 11) and "min -j 'run_lapw -p -I -NI -i 120 *-ec
>>> *0.00001 *-ec * 0.0001 -fc 1
>>> 2. with 400 k, div: (  8  5  8)   and   min -j 'run_lapw -p -I -NI -i
>>> 120 *-ec * 0.0001 *-ec * 0.0005 -fc 2'
>>>
>> -ec switch is used twice instead of ec and cc (it is by mistake)
>> In case 2 with less k-points and normal scf criteria (-ec 0.0001 -ec
>> 0.0005 -fc 2), I got minimized ENE than case 1. But the band gap is good
>> from case 1.
>>
>>
>> Results:
>>
>> 1. GAP 1.687 eV,    FER: 0.1030934295, ENE: -339059.11079128
>> 2. GAP  1.777 eV,   FER: 0.1004906191, ENE: -339059.12432403
>>
>> You see that band gap is in the error of /+- 0.01eV.
>>
>>
>>
>>
>> *[* next i tried with 1. with 1000 k, div: ( 11  7 11) and "min -j
>> 'run_lapw -p -I -NI -i 120 -ec 0.00001 -cc 0.0001 -fc 1   >> second -ec is
>> replaced by -cc 2. with 400 k, div: (  8  5  8)   and   min -j 'run_lapw -p
>> -I -NI -i 120 -ec 0.0001 -cc 0.0005 -fc 2'      *
>> *>> second -ec is replaced by -cc*
>> *and nothing happened scf immediately got exit and the structure was
>> already optimized]*
>>
>>>
>>>
>>> I did nothing special, just reduced rmt (5% and further rmt of "I" was
>>> reduced by 0.02).
>>> *Please correct me what is wrong here. Because usually PBE always
>>> underestimates the experimental band gap.*
>>>
>>> Kind regards
>>> Bhamu
>>>
>>
>>
>
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