[Wien] Structure optimization of Beta -Sn

shamik chakrabarti shamik15041981 at gmail.com
Thu Jun 4 07:45:16 CEST 2020


Dear Xavier Sir,

                      Thank you so much for your suggestions. I will
strictly follow it.

with kind regards,

On Thu, 4 Jun 2020 at 03:39, Xavier Rocquefelte <
xavier.rocquefelte at univ-rennes1.fr> wrote:

> Here is a cif file. You can see that Sn is on a Wyckoff position 4a, which
> means that you have 4 equivalent positions in the space group I 41/a m d.
>
> In WIEN2k, it leads to a case.struct file having only 2 equivalent
> positions, because only the positions in the primitive cell are shown in
> the case.struct file and here the cell is body-centered (I).
>
>
> The fact that you have 4 equivalent position in the case.struct file you
> sent to the list is clearly an indication that the structure is not
> correct.
>
> In addition, when starting a calculation you should first check the bond
> distances from the litterature, which is about 3.02 angtström for Sn-Sn.
> More precisely one tin is surrounded by 4 tin atoms with the same Sn-Sn
> distance.
>
>
> In the structure you sent to the list the Sn-Sn distances were 2.2
> angström!!! It is too small for such an element. It is why the geometry
> optimization goes wrong. Thus, the first thing to due before doing
> "run_lapw" is to check your data. To do so, you must check carefully:
>
>
> - case.outputnn --> bond distances and coordination
>
> - case.outputs  --> point group for each inequivalent atoms
>
> ...
>
>
> Regards
>
> Xavier
>
>
>
>
>
>
> Le 03/06/2020 à 23:54, Xavier Rocquefelte a écrit :
>
> Dear Fabien,
>
> I explained to Shamik that the structure he was using was not correct.
>
> I also sent cif and struct file.
>
> See below a proper case.struct file.
>
> Shamik could you please send email only to the wienlist to avoid multiple
> answers from the list and many people trying to help you without having all
> the details?
>
>
> blebleble
> B   LATTICE,NONEQUIV.ATOMS:  1 141 I41/amd
> MODE OF CALC=RELA unit=bohr
>  11.019938 11.019938  6.011975 90.000000 90.000000 90.000000
> ATOM   1: X=0.50000000 Y=0.25000000 Z=0.12500000
>           MULT= 2          ISPLIT=-2
>        1: X=0.00000000 Y=0.25000000 Z=0.37500000
> Sn1        NPT=  781  R0=.000010000 RMT= 2.50000     Z:  50.
> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                      0.0000000 1.0000000 0.0000000
>                      0.0000000 0.0000000 1.0000000
>   16      NUMBER OF SYMMETRY OPERATIONS
>  1 0 0 0.00000000
>  0 1 0 0.00000000
>  0 0 1 0.00000000
>        1
> -1 0 0 0.50000000
>  0-1 0 0.00000000
>  0 0 1 0.50000000
>        2
>  0-1 0 0.25000000
>  1 0 0 0.75000000
>  0 0 1 0.25000000
>        3
>  0 1 0 0.25000000
> -1 0 0 0.25000000
>  0 0 1 0.75000000
>        4
> -1 0 0 0.50000000
>  0 1 0 0.00000000
>  0 0-1 0.50000000
>        5
>  1 0 0 0.00000000
>  0-1 0 0.00000000
>  0 0-1 0.00000000
>        6
>  0 1 0 0.25000000
>  1 0 0 0.75000000
>  0 0-1 0.25000000
>        7
>  0-1 0 0.25000000
> -1 0 0 0.25000000
>  0 0-1 0.75000000
>        8
> -1 0 0 0.00000000
>  0-1 0 0.00000000
>  0 0-1 0.00000000
>        9
>  1 0 0 0.50000000
>  0 1 0 0.00000000
>  0 0-1 0.50000000
>       10
>  0 1 0 0.75000000
> -1 0 0 0.25000000
>  0 0-1 0.75000000
>       11
>  0-1 0 0.75000000
>  1 0 0 0.75000000
>  0 0-1 0.25000000
>       12
>  1 0 0 0.50000000
>  0-1 0 0.00000000
>  0 0 1 0.50000000
>       13
> -1 0 0 0.00000000
>  0 1 0 0.00000000
>  0 0 1 0.00000000
>       14
>  0-1 0 0.75000000
> -1 0 0 0.25000000
>  0 0 1 0.75000000
>       15
>  0 1 0 0.75000000
>  1 0 0 0.75000000
>  0 0 1 0.25000000
>       16
>
>
>
>
>
> Le 03/06/2020 à 21:38, Tran, Fabien a écrit :
>
> Using a RKmax above 7 should not lead to completely wrong results.
> One important point is how the lattice constants a and c were varied. In a
> meaningful way?
>
>
> ------------------------------
> *From:* Wien <wien-bounces at zeus.theochem.tuwien.ac.at>
> <wien-bounces at zeus.theochem.tuwien.ac.at> on behalf of shamik chakrabarti
> <shamik15041981 at gmail.com> <shamik15041981 at gmail.com>
> *Sent:* Wednesday, June 3, 2020 8:40 PM
> *To:* A Mailing list for WIEN2k users
> *Subject:* Re: [Wien] Structure optimization of Beta -Sn
>
> Dear Dr. Tran,
>
>                   I have used both plain GGA & nlvdw independently & in
> both cases the results are same. I have used Rmr*Kmax=9 for nlvdw & 7 for
> GGA. Do you think moving to larger Rmt*Kmax may solve the problem? I am
> currently going through the literature you have sent..
>
> with regards,
>
> On Wed, 3 Jun 2020 at 23:53, Tran, Fabien <fabien.tran at tuwien.ac.at>
> wrote:
>
>> At first sight you struct file seems ok, but this is difficult to help
>> you without more details. For instance: Which functional have you used? Are
>> you keeping the c/a ratio fixed? Have you looked into the literature:
>>
>> https://aip.scitation.org/doi/abs/10.1063/1.4948434
>>
>>
>> ------------------------------
>> *From:* Wien <wien-bounces at zeus.theochem.tuwien.ac.at> on behalf of
>> shamik chakrabarti <shamik15041981 at gmail.com>
>> *Sent:* Wednesday, June 3, 2020 8:06 PM
>> *To:* A Mailing list for WIEN2k users
>> *Subject:* [Wien] Structure optimization of Beta -Sn
>>
>> Dear wien2k users,
>>
>>                                  I am trying to optimize the structure of
>> Beta - Sn. However, even after 20% increment of the volume there is no sign
>> of energy minima. I am attaching the struct file herewith this mail
>> for your consideration.
>>
>> Looking forward to hearing from you.
>>
>> with regards,
>>
>> --
>> Dr. Shamik Chakrabarti
>> Research Fellow
>> Department of Physics
>> Indian Institute of Technology Patna
>> Bihta-801103
>> Patna
>> Bihar, India
>> _______________________________________________
>> Wien mailing list
>> Wien at zeus.theochem.tuwien.ac.at
>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>> SEARCH the MAILING-LIST at:
>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>>
>
>
> --
> Dr. Shamik Chakrabarti
> Research Fellow
> Department of Physics
> Indian Institute of Technology Patna
> Bihta-801103
> Patna
> Bihar, India
>
> _______________________________________________
> Wien mailing listWien at zeus.theochem.tuwien.ac.athttp://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
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> --
> ------------------------
> Institut des Sciences Chimiques de Rennes (ISCR)
> Univ Rennes - CNRS - UMR6226, Francehttps://iscr.univ-rennes1.fr/cti/people/permanent-staff/rocquefelte-xavier
> ------------------------
> ICAMM2019 : VASP Workshop and International Materials Modelling Conf
> June 26-July 3 2019, Rennes Franceicamm2019.sciencesconf.org  : Registration opening soon, see you there!
>
>
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> ------------------------
> Institut des Sciences Chimiques de Rennes (ISCR)
> Univ Rennes - CNRS - UMR6226, Francehttps://iscr.univ-rennes1.fr/cti/people/permanent-staff/rocquefelte-xavier
> ------------------------
> ICAMM2019 : VASP Workshop and International Materials Modelling Conf
> June 26-July 3 2019, Rennes Franceicamm2019.sciencesconf.org  : Registration opening soon, see you there!
>
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> Wien at zeus.theochem.tuwien.ac.at
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-- 
Dr. Shamik Chakrabarti
Research Fellow
Department of Physics
Indian Institute of Technology Patna
Bihta-801103
Patna
Bihar, India
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