Yea dear Linh, I have used the converged cell parameter from vc-relax calculation for scf run,<br><br>Thnaks,<br>mohnish<br><br><div class="gmail_quote">On Sun, Apr 18, 2010 at 8:33 PM, Ngoc Linh Nguyen <span dir="ltr"><<a href="mailto:nnlinh@sissa.it">nnlinh@sissa.it</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div class="im"><br>
> Dear Hanyu !<br>
> Thanks for your reply. As you now the default value<br>
> for<br>
> the pressure in PWSCF is 0.5.<br>
<br>
</div>This value should be 0.0 as the default value (see in input PW website)<br>
<div class="im"><br>
> I am using that value as convergence<br>
> threshold<br>
> but when I am doing scf calculation with the geometrical parameters value<br>
> obtained from the vc-relax calculation the pressure value is different<br>
> from<br>
> vc-relax final run. And as you know pressure will effect the phonon<br>
> dispresion relation..Can you please give me any suggestion,<br>
<br>
</div>Before doing scf calculations, have you changed the cell-parameters in scf<br>
input file as same as the converged cell-parameters from vc-relax?<br>
<br>
Best regards,<br>
<br>
Linh<br>
<div><div></div><div class="h5"><br>
<br>
<br>
><br>
> Thanks alot,<br>
> MOHNISH<br>
><br>
> On Sun, Apr 18, 2010 at 3:00 PM, Hanyu <<a href="mailto:ouuing@gmail.com">ouuing@gmail.com</a>> wrote:<br>
><br>
>> dear mohnish :<br>
>> I think you should check it carefully again. I don't think it should<br>
>> be happen. In fact, the stress of scf and vc-relax should be the same.<br>
>> but if the stress is not the hydrostatic pressure, the result is not<br>
>> be believed. you have to relax the structure until the stress of the<br>
>> phase is what you want.<br>
>><br>
>> best regards.<br>
>><br>
>> Hanyu<br>
>><br>
>> On Sun, Apr 18, 2010 at 11:16 AM, mohnish pandey<br>
>> <<a href="mailto:mohnish.iitk@gmail.com">mohnish.iitk@gmail.com</a>><br>
>> wrote:<br>
>> > Dear users,<br>
>> > I want to do phonon calculation for some structures,<br>
>> but<br>
>> > after geometry optimization when I am using optimized geometry<br>
>> parameters<br>
>> > for scf calculation there is difference in stress of scf calculation<br>
>> and<br>
>> > vc-relax calculation which is changing phonon dispersion. Can anybody<br>
>> please<br>
>> > tell me if there is any option to use the data of relax or vc-relax<br>
>> > calculation for phonon dispersion.. Or can I doing phonon calculation<br>
>> along<br>
>> > with relax or vc-relax calculation.?<br>
>> > Thanks a lot in advance,<br>
>> ><br>
>> > --<br>
>> > Regards,<br>
>> > MOHNISH,<br>
>> > -----------------------------------------------------------------<br>
>> > Mohnish Pandey<br>
>> > Y6927262,4th Year dual degree student,<br>
>> > Department of Chemical Engineering,<br>
>> > IIT KANPUR<br>
>> > 09235721300<br>
>> > -----------------------------------------------------------------<br>
>> ><br>
>> > _______________________________________________<br>
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>> > <a href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br>
>> > <a href="http://www.democritos.it/mailman/listinfo/pw_forum" target="_blank">http://www.democritos.it/mailman/listinfo/pw_forum</a><br>
>> ><br>
>> ><br>
>><br>
>><br>
>><br>
>> --<br>
>> -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=**=-=**=-=**=-=*=-=*=-=*=-=*=-=*=-<br>
</div></div>>> Hanyu Liu(刘寒雨),<br>
<div class="im">>> MS.<br>
>> State key Laboratory of Superhard Materials, Jilin University, China<br>
>> Email: <a href="mailto:liuhanyu08@mails.jlu.edu.cn">liuhanyu08@mails.jlu.edu.cn</a> <a href="mailto:ouuing@gmail.com">ouuing@gmail.com</a><br>
>> _______________________________________________<br>
>> Pw_forum mailing list<br>
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>> <a href="http://www.democritos.it/mailman/listinfo/pw_forum" target="_blank">http://www.democritos.it/mailman/listinfo/pw_forum</a><br>
>><br>
><br>
><br>
><br>
> --<br>
> Regards,<br>
> MOHNISH,<br>
> -----------------------------------------------------------------<br>
> Mohnish Pandey<br>
> Y6927262,4th Year dual degree student,<br>
> Department of Chemical Engineering,<br>
> IIT KANPUR<br>
> 09235721300<br>
> -----------------------------------------------------------------<br>
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><br>
<br>
<br>
</div>-----------------------------------------------------<br>
Nguyen Ngoc Linh, PhD Student<br>
c/o: SISSA & CNR-INFM Democritos,<br>
via Beirut 2-4, 34014 Trieste (Italy)<br>
email: <a href="mailto:nnlinh@sissa.it">nnlinh@sissa.it</a><br>
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</div></div></blockquote></div><br><br clear="all"><br>-- <br>Regards,<br>MOHNISH,<br>-----------------------------------------------------------------<br>Mohnish Pandey<br>Y6927262,4th Year dual degree student,<br>Department of Chemical Engineering,<br>
IIT KANPUR<br>09235721300<br>-----------------------------------------------------------------<br>