Re: [Wien] About comparable energy between GGA & nlvdw

[shamik chakrabarti]

Dear Laurence Sir,

 Thank you so much for your response. It clears my
doubt.

with kind regards,

On Wed, 11 Mar 2020 at 12:03, Laurence Marks 
wrote:

> You must use the same functional, RKMAX*min(RMT) (be careful), comparable
> k-pt density.
>
> _
> Professor Laurence Marks
> "Research is to see what everybody else has seen, and to think what nobody
> else has thought", Albert Szent-Gyorgi
> www.numis.northwestern.edu
>
> On Wed, Mar 11, 2020, 01:17 shamik chakrabarti 
> wrote:
>
>> Dear Wien2k users,
>>
>>If I want to calculate the formation energy of A
>> from the reaction B+C=A by the formula E(A)-E(B)-E(C) should I have to
>> simulate all the three components by the same correlation i.e. either by
>> GGA or by nlvdw (same correlation for all the components)
>>  OR
>> I should choose the correlation which gives lower energy of the
>> components either by GGA or by nlvdw.
>>
>> The main issue is that I am talking about relative energy & not the
>> accurate individual energy.
>>
>> Looking forward to your response eagerly.
>>
>> with regards,
>>
>> --
>> Dr. Shamik Chakrabarti
>> Research Fellow
>> Department of Physics
>> Indian Institute of Technology Patna
>> Bihta-801103
>> Patna
>> Bihar, India
>> ___
>> Wien mailing list
>> Wien@zeus.theochem.tuwien.ac.at
>>
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>> SEARCH the MAILING-LIST at:
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>>
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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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Re: [Wien] About comparable energy between GGA & nlvdw

[Laurence Marks]

You must use the same functional, RKMAX*min(RMT) (be careful), comparable
k-pt density.

_
Professor Laurence Marks
"Research is to see what everybody else has seen, and to think what nobody
else has thought", Albert Szent-Gyorgi
www.numis.northwestern.edu

On Wed, Mar 11, 2020, 01:17 shamik chakrabarti 
wrote:

> Dear Wien2k users,
>
>If I want to calculate the formation energy of A
> from the reaction B+C=A by the formula E(A)-E(B)-E(C) should I have to
> simulate all the three components by the same correlation i.e. either by
> GGA or by nlvdw (same correlation for all the components)
>  OR
> I should choose the correlation which gives lower energy of the components
> either by GGA or by nlvdw.
>
> The main issue is that I am talking about relative energy & not the
> accurate individual energy.
>
> Looking forward to your response eagerly.
>
> with regards,
>
> --
> Dr. Shamik Chakrabarti
> Research Fellow
> Department of Physics
> Indian Institute of Technology Patna
> Bihta-801103
> Patna
> Bihar, India
> ___
> Wien mailing list
> Wien@zeus.theochem.tuwien.ac.at
>
> https://urldefense.com/v3/__http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien__;!!Dq0X2DkFhyF93HkjWTBQKhk!HqgG51MpfzOARNVyYdlXbQ1ImIzUvaT-uwOH6wiCylWnWE3NoGcM_ircw6n7xvVzj0zI6Q$
> SEARCH the MAILING-LIST at:
> https://urldefense.com/v3/__http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html__;!!Dq0X2DkFhyF93HkjWTBQKhk!HqgG51MpfzOARNVyYdlXbQ1ImIzUvaT-uwOH6wiCylWnWE3NoGcM_ircw6n7xvVd_7PqzA$
>
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[Wien] About comparable energy between GGA & nlvdw

[shamik chakrabarti]

Dear Wien2k users,

   If I want to calculate the formation energy of A
from the reaction B+C=A by the formula E(A)-E(B)-E(C) should I have to
simulate all the three components by the same correlation i.e. either by
GGA or by nlvdw (same correlation for all the components)
 OR
I should choose the correlation which gives lower energy of the components
either by GGA or by nlvdw.

The main issue is that I am talking about relative energy & not the
accurate individual energy.

Looking forward to your response eagerly.

with regards,

-- 
Dr. Shamik Chakrabarti
Research Fellow
Department of Physics
Indian Institute of Technology Patna
Bihta-801103
Patna
Bihar, India
___
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Re: [Wien] Volume optimization of Sulphur

[shamik chakrabarti]

Dear Prof. Blaha,

   Thank you so much for your elaborate reply. This
will be very helpful for me.

Thanks once again.

with regards,

On Tue, 10 Mar 2020 at 17:23, Peter Blaha 
wrote:

> I think F. Tran already gave you the hint about "primitive R cell" and
> "conventional H cell".
>
> The volume of the R cell is 3 times smaller than that of the H cell.
>
> Wien2k gives H lattice parameters, but makes the calculation internally
> in R cell.
>
> So yes, if you get an equilibrium volume which does not fit your
> expectations, it is because of your wrong assumptions aber the actual
> lattice.
>
> It is the same as for a FCC cubic cell: What is the volume of the
> primitive (R) cell of an FCC lattice: it is NOT a**3, but a**3 / 4.
>
> 
> Besides this: the optimize scribt gives you a volume, but of course also
> total energies and you can easily see, which of your struct files
> corresponds (nearly) to the optimized volume (the one with the lowest
> energy). And you find the corresponding a,c values directly in this
> struct file.
>
> It can't be that difficult to get the optimized lattice parameters.
>
> PS: Please read the UG (struct file) about R-lattices
>
> On 3/10/20 11:03 AM, shamik chakrabarti wrote:
> > I think we should multiply the printed volume by 3 to get the actual
> > volume as the cell described in rhombohedral lattice is 3 times larger
> > than the hexagonal unit cell...I am sending a link which gives this clue
> >
> > http://www.globalsino.com/EM/page3546.html
> >
> > Please correct me if I am wrong!
> >
> > with regards,
> >
> > On Tue, 10 Mar 2020 at 15:22, Tran, Fabien  > > wrote:
> >
> > Probably. In case.struct, the lattice constants and angles are for
> > the hexagonal cell, while atoms positions are with respect to
> > rhombohedral.
> >
> >
> >
>  
> > *From:* Wien  > > on behalf of
> > shamik chakrabarti  > >
> > *Sent:* Tuesday, March 10, 2020 10:46 AM
> > *To:* A Mailing list for WIEN2k users
> > *Subject:* Re: [Wien] Volume optimization of Sulphur
> > 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
> > mailto:shamik15041...@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
> > mailto:fabien.t...@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  > > on behalf
> > of shamik chakrabarti  > >
> > *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
> > mailto:shamik15041...@gmail.com>>
> > wrote:
> >
> > Dear Lyudmila Sir,
> >
> >   To remove the confusion I am
> > sending the struct file which have been used in our
> >  

Re: [Wien] Volume optimization of Sulphur

[Peter Blaha]

I think F. Tran already gave you the hint about "primitive R cell" and 
"conventional H cell".


The volume of the R cell is 3 times smaller than that of the H cell.

Wien2k gives H lattice parameters, but makes the calculation internally 
in R cell.


So yes, if you get an equilibrium volume which does not fit your 
expectations, it is because of your wrong assumptions aber the actual 
lattice.


It is the same as for a FCC cubic cell: What is the volume of the 
primitive (R) cell of an FCC lattice: it is NOT a**3, but a**3 / 4.



Besides this: the optimize scribt gives you a volume, but of course also 
total energies and you can easily see, which of your struct files 
corresponds (nearly) to the optimized volume (the one with the lowest 
energy). And you find the corresponding a,c values directly in this 
struct file.


It can't be that difficult to get the optimized lattice parameters.

PS: Please read the UG (struct file) about R-lattices

On 3/10/20 11:03 AM, shamik chakrabarti wrote:
I think we should multiply the printed volume by 3 to get the actual 
volume as the cell described in rhombohedral lattice is 3 times larger 
than the hexagonal unit cell...I am sending a link which gives this clue


http://www.globalsino.com/EM/page3546.html

Please correct me if I am wrong!

with regards,

On Tue, 10 Mar 2020 at 15:22, Tran, Fabien > wrote:


Probably. In case.struct, the lattice constants and angles are for
the hexagonal cell, while atoms positions are with respect to
rhombohedral.



*From:* Wien mailto:wien-boun...@zeus.theochem.tuwien.ac.at>> on behalf of
shamik chakrabarti mailto:shamik15041...@gmail.com>>
*Sent:* Tuesday, March 10, 2020 10:46 AM
*To:* A Mailing list for WIEN2k users
*Subject:* Re: [Wien] Volume optimization of Sulphur
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
mailto:shamik15041...@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
mailto:fabien.t...@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 mailto:wien-boun...@zeus.theochem.tuwien.ac.at>> on behalf
of shamik chakrabarti mailto:shamik15041...@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
mailto:shamik15041...@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

Re: [Wien] Volume optimization of Sulphur

[shamik chakrabarti]

I think we should multiply the printed volume by 3 to get the actual volume
as the cell described in rhombohedral lattice is 3 times larger than the
hexagonal unit cell...I am sending a link which gives this clue

http://www.globalsino.com/EM/page3546.html

Please correct me if I am wrong!

with regards,

On Tue, 10 Mar 2020 at 15:22, Tran, Fabien  wrote:

> Probably. In case.struct, the lattice constants and angles are for the
> hexagonal cell, while atoms positions are with respect to rhombohedral.
>
>
> --
> *From:* Wien  on behalf of
> shamik chakrabarti 
> *Sent:* Tuesday, March 10, 2020 10:46 AM
> *To:* A Mailing list for WIEN2k users
> *Subject:* Re: [Wien] Volume optimization of Sulphur
>
> 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 
> 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 
>> 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  on behalf of
>>> shamik chakrabarti 
>>> *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 <
>>> shamik15041...@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
>>> ___
>>> Wien mailing list
>>> Wien@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
>>
>
>
> --
> Dr. Shamik Chakrabarti
> Research Fellow
> Department of Physics
> Indian Institute of Technology Patna
> Bihta-801103
> Patna
> Bihar, India
> ___
> Wien mailing list
> Wien@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
___
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Re: [Wien] Volume optimization of Sulphur

[Tran, Fabien]

Probably. In case.struct, the lattice constants and angles are for the 
hexagonal cell, while atoms positions are with respect to rhombohedral.



From: Wien  on behalf of shamik 
chakrabarti 
Sent: Tuesday, March 10, 2020 10:46 AM
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] Volume optimization of Sulphur

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 
mailto:shamik15041...@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 
mailto:fabien.t...@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 
mailto:wien-boun...@zeus.theochem.tuwien.ac.at>>
 on behalf of shamik chakrabarti 
mailto:shamik15041...@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 
mailto:shamik15041...@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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Re: [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 
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 
> 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  on behalf of
>> shamik chakrabarti 
>> *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 <
>> shamik15041...@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
>> ___
>> Wien mailing list
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>> 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
>


-- 
Dr. Shamik Chakrabarti
Research Fellow
Department of Physics
Indian Institute of Technology Patna
Bihta-801103
Patna
Bihar, India
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Re: [Wien] Volume optimization of Sulphur

[shamik chakrabarti]

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  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  on behalf of
> shamik chakrabarti 
> *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 
> 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
> ___
> Wien mailing list
> Wien@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
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Re: [Wien] Volume optimization of Sulphur

[Tran, Fabien]

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  on behalf of shamik 
chakrabarti 
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 
mailto:shamik15041...@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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Re: [Wien] Volume optimization of Sulphur

[shamik chakrabarti]

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 
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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Re: [Wien] Volume optimization of Sulphur

[Lyudmila Dobysheva]

10.03.2020 10:45, shamik chakrabarti wrote:
> I have started volume optimization of S using a cif file attached
> herewith using nlvdw. The simulation goes well and presented a
> minima in the volume vs energy curve. However, when I opt for the
> calculation of unit cell volume for R_3 (space group no. 148) crystal
> system with the formula V = a^2 c sin60, the lattice parameter comes
> out to be too much smaller (a=b= 7.6 A in comparison to experimental
> a=b=10.818 A).

As far as I understand you have done a volume opt of a struct file 1 
with good results (?) and a volume opt of a struct file 2 R_3 with bad 
results (?).
So, you are to send the two struct files and some other input files. Now 
it is difficult to understand the problem.


Best wishes
Lyudmila Dobysheva
--
http://ftiudm.ru/content/view/25/103/lang,english/
Physics-Techn.Institute,
Udmurt Federal Research Center, Ural Br. of Rus.Ac.Sci.
426000 Izhevsk Kirov str. 132
Russia
---
Tel. +7 (34I2)43-24-59 (office), +7 (9I2)OI9-795O (home)
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[Wien] Volume optimization of Sulphur

[shamik chakrabarti]

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


S_Vopt_initial.struct
Description: Binary data
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