Dear Eduardo Ariel Menendez Proupin, I forget to answer other questions. If we relaxed the tube after compression there is no net force on carbon atoms so I did not relax the system after compression. *Have you used a finite nanotube and computed the forces upon the atoms of the edge?*.....> A finite nano-tube? I consider a unit cell (which can make an infinite tube ) and calculate force between atoms. Is there any problem?
Mohsen Modarresi On Thu, Sep 23, 2010 at 1:21 AM, mohsen modaresi <modaresi.mohsen at gmail.com>wrote: > Dear Eduardo Ariel Menendez Proupin, > At first i relaxed nano-tube and obtain the position of carbon atoms in the > ground state. Then i decrease the tube length. A in the relation is the area > of nano-tube (A=pi*R*R which R is the radius of tube). F is the atomic force > in the Z axis which can be calculated by using Q.E. > I think it is better to calculate total energy in some configuration and > use (F=dE/dz, where E is the total energy in different configuration). > Is there any problem in this procedure? > > > > On Thu, Sep 23, 2010 at 12:58 AM, Eduardo Ariel Menendez Proupin < > eariel99 at gmail.com> wrote: > >> Hi, >> I think we always know what WE do, but not all of what computers do :-(. >> >> Mohsen, did you relaxed the atoms after the compression? Why did you >> calculate force and not stress. Have you used a finite nanotube and computed >> the forces upon the atoms of the edge? Finally, how is defined A in >> E=(F/A)/((L-L0)/L0) >> for the case of a single nonotube? >> Best regards >> Eduardo >> >> Eduardo Menendez >> Departamento de Fisica >> Facultad de Ciencias >> Universidad de Chile >> Phone: (56)(2)9787439 >> URL: >> http://fisica.ciencias.uchile.cl/~emenendez<http://fisica.ciencias.uchile.cl/%7Eemenendez> >> >> Let's pray for the 33 trapped miners! Four months to rescue >> >> >> >>> ---------- Mensaje reenviado ---------- >>> >>> From: Stefano Baroni <baroni at sissa.it> >>> To: PWSCF Forum <pw_forum at pwscf.org> >>> Date: Wed, 22 Sep 2010 19:43:15 +0200 >>> >>> Subject: Re: [Pw_forum] Young's Modulus >>> For that, also LRT akkows one to know what one is doing ... ;-) >>> SB >>> >>> On Sep 22, 2010, at 7:30 PM, Mehmet Topsakal wrote: >>> >>> Dear Eyvaz, >>> >>> I think you omitted one more thing to mention. Brute-force method also >>> allows one to know what he is doing. >>> >>> >>> >>> On Wed, Sep 22, 2010 at 8:14 PM, Eyvaz Isaev <eyvaz_isaev at yahoo.com> >>> wrote: >>> >>>> Hi, >>>> >>>> Yes, you are right about Abinit for elastic constants calculations. The >>>> main question is which method (Abinit or via total energy) is easier >>>> and less time-consuming. >>>> >>>> Bests, >>>> Eyvaz. >>>> ------------------------------------------------------------------- >>>> Prof. Eyvaz Isaev, >>>> Department of Physics, Chemistry, and Biology (IFM), Linkoping >>>> University, Sweden >>>> Theoretical Physics Department, Moscow State Institute of Steel & >>>> Alloys, Russia, >>>> isaev at ifm.liu.se, eyvaz_isaev at yahoo.com >>>> >>> >>>> >> -- >> >> >> . >> >> >> _______________________________________________ >> Pw_forum mailing list >> Pw_forum at pwscf.org >> http://www.democritos.it/mailman/listinfo/pw_forum >> >> > > > -- > Mohsen Modarresi, > PhD student of Solid State Physics, Ferdowsi University of Mashhad, Iran. > Phone +98-9133452131 > > -- Mohsen Modarresi, PhD student of Solid State Physics, Ferdowsi University of Mashhad, Iran. Phone +98-9133452131 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20100923/ab8c3061/attachment-0001.htm
