[Wien] Volume optimization of Sulphur

[shamik chakrabarti]

It may be a clue for solving the above problem;

              In the struct file (as seen in the GUI) a line remains added
:   "positions must be specified in rhombohedral coordinates!"

Looking forward to your response eagerly.

with regards,

On Tue, 10 Mar 2020 at 14:51, shamik chakrabarti <shamik15041981 at gmail.com>
wrote:

> Dear Prof. Tran,
>
>                   a^2 c Sin 60 is the volume of the rhombohedral cell
> having lattice parameter a=b & c. I have used the same formula for
> hexagonal SnS2 and got very good results. I think somehow the printed
> volume  is almost 1/2.8 th of the actual value needed. I guess it is
> something related to R_3 crystal system...........
>
> with regards,
>
> On Tue, 10 Mar 2020 at 14:36, Tran, Fabien <fabien.tran at tuwien.ac.at>
> wrote:
>
>> WIEN2k does the calculations in the primitive unit cell, whose volume is
>> given by :VOL in case.scf
>>
>> Is a^2 c Sin 60 not the volume of the conventional cell?
>>
>> You can visualize the primitive and conventional cells of case.struct
>> with xcrysden (press F3 or F4).
>>
>>
>> ------------------------------
>> *From:* Wien <wien-bounces at zeus.theochem.tuwien.ac.at> on behalf of
>> shamik chakrabarti <shamik15041981 at gmail.com>
>> *Sent:* Tuesday, March 10, 2020 9:58 AM
>> *To:* A Mailing list for WIEN2k users
>> *Subject:* Re: [Wien] Volume optimization of Sulphur
>>
>> Dear Wien2k users,
>>
>>                               I am also certain that I am not doing any
>> mistake in the formula  of Volume=a^2 c Sin 60. However, the V0 printed in
>> the window showing the fitted BM curve is coming much less than that
>> expected from  a^2 c Sin 60 . What could be the cause? Is it related to the
>> space group R_3 (space group no. 148)?
>>
>> Looking forward to your reply eagerly.
>>
>> with regards,
>>
>>
>> On Tue, 10 Mar 2020 at 13:11, shamik chakrabarti <
>> shamik15041981 at gmail.com> wrote:
>>
>>> Dear Lyudmila Sir,
>>>
>>>                          To remove the confusion I am sending the struct
>>> file which have been used in our simulation. I have good results as far as
>>> the volume optimization curve is concerned. However, while calculating the
>>> lattice parameters using the formula V = a^2 c sin60 I got the low value of
>>> lattice parameters. My query is
>>> (1) Whether I have done something wrong in the formula itself?
>>> (2) While GGA is better than nlvdw in this case?
>>>
>>> with regards,
>>>
>>> --
>>> Dr. Shamik Chakrabarti
>>> Research Fellow
>>> Department of Physics
>>> Indian Institute of Technology Patna
>>> Bihta-801103
>>> Patna
>>> Bihar, India
>>>
>>
>>
>> --
>> Dr. Shamik Chakrabarti
>> Research Fellow
>> Department of Physics
>> Indian Institute of Technology Patna
>> Bihta-801103
>> Patna
>> Bihar, India
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>
>
> --
> Dr. Shamik Chakrabarti
> Research Fellow
> Department of Physics
> Indian Institute of Technology Patna
> Bihta-801103
> Patna
> Bihar, India
>


-- 
Dr. Shamik Chakrabarti
Research Fellow
Department of Physics
Indian Institute of Technology Patna
Bihta-801103
Patna
Bihar, India
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