[Wien] Band gap calculation

[Gavin Abo]

By the way, I suspect that the full convergence tests package might only 
do the k-point convergence test for a non-hf scf as adjusted by "x kgen".

If your doing an hf calculation, does the test_conv-5.0.tar.gz have an 
hf feature that uses the run_kgenhf_lapw for the k-point convergence 
test for the scf [ 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg19131.html 
].

Also for the band structure k-point convergence test, is 
test_conv-5.0.tar.gz changing how fine the mesh is in case.klist_band 
(generated manually by hand, automatically by own script or XCrysDen?) 
before proceeding with run_bandplothf_lapw and "x spagehetti -hf" for an 
hf calculation [ 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg18937.html 
, 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg19403.html 
].

On 12/23/2019 1:33 AM, Gavin Abo wrote:
> I don't recall seeing "test_conv-5.0.tar.gz" before.  I'm guessing 
> that is the newer version of the full convergence tests package at [1] 
> (unsupported at least by this group), which seems to not be accessible 
> to the public (and likely only accessible to and perhaps supported by 
> the private group [2]).
>
> I'm guessing the algorithm that gets the gap value from the valence 
> band maximum (VBM) and conduction band minimum (CBM) is not accurate 
> for your calculation case.  Therefore, I would most likely go with the 
> gap that you get yourself from the raw data (case.spaghetti_ene [3] or 
> [4]) of the band structure plot from spaghetti.
>
> If the differences are small like in [5], a percent difference [6] of 
> about 2% [= (1.54 eV - 1.51 eV)/{(1.54 eV + 1.51 eV)/2}*100%] seems 
> acceptable.  I believe greater than about 5% in when you should be 
> concerned [7].
>
> [1] 
> http://wien2k-algerien1970.blogspot.com/2016/09/the-full-version-of-conversgence-tests.html
> [2] https://www.facebook.com/groups/wien2k.Algeria/
> [3] 
> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg15255.html
> [4] 
> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg15258.html
> [5] 
> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg19405.html
> [6] 
> https://www.webassign.net/question_assets/ncsucalcphysmechl3/percent_error/manual.html
> [7] https://socratic.org/questions/what-percent-error-is-too-high
>
> On 12/22/2019 11:36 PM, Peeyush kumar kamlesh wrote:
>> Dear Gavin Sir,
>> Thank you for your response.
>> I did k-point convergence test by a test package 
>> "test_conv-5.0.tar.gz". I dont know whether it is gives completely 
>> satisfactory results or not. If you have any other package for kpt 
>> convergence kindly let me know, so that i can do the right 
>> calculations. Also I used non shifted k-mash in the calculations of 
>> the band gap.
>>
>> Thank you so much!
>> Regards
>> Peeyush Kamlesh
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