[Wien] core leakage problem

[Laurence Marks]

No.
On Jul 13, 2015 4:37 PM, "Muhammad Sajjad" <sajjadpu at gmail.com> wrote:

>   Thank you professor L.Marks
>  I followed your first two points and ran calculation. I did not fix the
> center of slab but relax the whole structure and the minimized forces are
> :FOR001:   1.ATOM      60.004776      -0.000002      -0.000003
> 60.004776 total forces
> :FOR002:   2.ATOM      33.431081      -0.000003       0.000003
> 33.431081 total forces
> :FOR003:   3.ATOM      33.431078       0.000003      -0.000003
> 33.431078 total forces
> :FOR004:   4.ATOM      60.004776       0.000003       0.000003
> 60.004776 total forces
> :FOR005:   5.ATOM      33.434049       0.000002       0.000001
> -33.434049 total forces
> :FOR006:   6.ATOM      60.056705       0.000001      -0.000001
> -60.056705 total forces
> :FOR007:   7.ATOM      60.056708      -0.000001       0.000000
> -60.056708 total forces
> :FOR008:   8.ATOM      33.434051      -0.000002      -0.000001
> -33.434051 total forces
> :FOR009:   9.ATOM      32.291125       0.000000       0.000000
> -32.291125 total forces
> :FOR010:  10.ATOM      32.291121       0.000000       0.000000
> -32.291121 total forces
> :FOR011:  11.ATOM      32.312836       0.000000       0.000000
> 32.312836 total forces
> :FOR012:  12.ATOM      32.312836       0.000000       0.000000
> 32.312836 total forces
>
>  Is this calculation reliable?
>
> On Sun, Jul 12, 2015 at 4:33 PM, Laurence Marks <L-marks at northwestern.edu>
> wrote:
>
>> A few points:
>>
>>  a) Your Si-H distance is too small, it should be about 1.45 Angstroms
>> and you have 1.0 Angstroms. With a better value most of your problems will
>> probably go away.
>>
>>  b) To do a surface calculation you must use the DFT equilibrium lattice
>> parameters, not the bulk ones. If you do not the results will be wrong.
>>
>>  c) For a surface calculation you need the distance between the two
>> surfaces across the vacuum gap to be equal to or smaller than the distance
>> between the two surfaces across the crystal. I personally prefer to make
>> the bulk material twice as wide as the vacuum gap, so the atomic
>> relaxations at the center of the crystal are as small as possible. (Some
>> people will fix the center of the slab, but I think that is bad physics.)
>> Your bulk crystal is way too small.
>>
>> On Sun, Jul 12, 2015 at 7:27 AM, Muhammad Sajjad <sajjadpu at gmail.com>
>> wrote:
>>
>>>   Dear All
>>>  I am performing structural relaxation for Si (100) with H at its top
>>> and bottom (structure is attached, vacuum is 12 A).  I have inspect the
>>> mailing list in detail (like
>>> http://www.wien2k.at/reg_user/textbooks/DFT_and_LAPW_2nd.pdf AND
>>> http://www.mail-archive.com/search?q=core+leakage&l=wien%40zeus.theochem.tuwien.ac.at)
>>> and have resolved the issue by selecting SE -12, but the calculation hang
>>> out after LAPW0. Inspection of lapw1_1.error message is "Error in LAPW1".
>>> Please suggest me the possible solution.
>>>
>>>  One more thing I found in the list "
>>>
>>> If
>>> you have core leakage, inspect in case.outputst whether you can take
>>> some high-lying core states as valence states instead
>>>
>>> "
>>>  Is it possible to make it manually with same SE ? or simple done by
>>> lowering down SE as I did?
>>>
>>>  Many thanks
>>>
>>>
>>
>>
>>   --
>>  Professor Laurence Marks
>> Department of Materials Science and Engineering
>> Northwestern University
>> www.numis.northwestern.edu
>> Corrosion in 4D: MURI4D.numis.northwestern.edu
>> Co-Editor, Acta Cryst A
>> "Research is to see what everybody else has seen, and to think what
>> nobody else has thought"
>> Albert Szent-Gyorgi
>>
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>>
>>
>
>
> --
>  Kind Regards
> Muhammad Sajjad
> Post Doctoral Fellow
> KAUST, KSA.
>
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