Dear Eduardo Ariel Menendez Proupin,<br>I forget to answer other questions.<br>If we relaxed the tube after <span style="font-family: arial,sans-serif; font-size: 13px; border-collapse: collapse;">compression there is no net force on carbon atoms so I did not relax the system after compression.<br>
</span><span style="font-family: arial,sans-serif; font-size: 13px; border-collapse: collapse;"><b>Have you used a finite nanotube and computed the forces upon the atoms of the edge?</b>.....> A finite nano-tube? I consider a unit cell (which can make an infinite tube ) and calculate force between atoms.<br>
Is there any problem?<br><br>Mohsen Modarresi </span><br><br><div class="gmail_quote">On Thu, Sep 23, 2010 at 1:21 AM, mohsen modaresi <span dir="ltr"><<a href="mailto:modaresi.mohsen@gmail.com">modaresi.mohsen@gmail.com</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;">Dear Eduardo Ariel Menendez Proupin,<br>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.<br>
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).<br>Is there any problem in this procedure?<br> <br><br><br><div class="gmail_quote">
<div><div></div><div class="h5">
On Thu, Sep 23, 2010 at 12:58 AM, Eduardo Ariel Menendez Proupin <span dir="ltr"><<a href="mailto:eariel99@gmail.com" target="_blank">eariel99@gmail.com</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div><div></div><div class="h5">
<span style="font-family: arial,sans-serif; font-size: 13px; border-collapse: collapse;">Hi, </span><div><span style="font-family: arial,sans-serif; font-size: 13px; border-collapse: collapse;">I think we always know what WE do, but not all of what computers do :-(. </span></div>
<div><span style="font-family: arial,sans-serif; font-size: 13px; border-collapse: collapse;"><br></span></div><div><span style="font-family: arial,sans-serif; font-size: 13px; border-collapse: collapse;">Mohsen, did you relaxed the atoms after the compression? Why d</span><span style="font-family: arial,sans-serif; font-size: 13px; border-collapse: collapse;">id 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 </span><span style="font-family: arial,sans-serif; font-size: 13px; border-collapse: collapse;"> E=(F/A)/((L-L0)/L0) for the case of a single nonotube?</span></div>
<div><span style="font-family: arial,sans-serif; font-size: 13px; border-collapse: collapse;">Best regards</span></div><div><span style="font-family: arial,sans-serif; font-size: 13px; border-collapse: collapse;">Eduardo</span></div>
<div><span style="font-family: arial,sans-serif; font-size: 13px; border-collapse: collapse;"><br></span></div><div><span style="font-family: arial,sans-serif; font-size: 13px; border-collapse: collapse;"><span style="border-collapse: separate; font-family: arial; font-size: small;">Eduardo Menendez<br>
Departamento de Fisica<br>Facultad de Ciencias<br>Universidad de Chile<br>Phone: (56)(2)9787439<br>URL: <a href="http://fisica.ciencias.uchile.cl/%7Eemenendez" target="_blank">http://fisica.ciencias.uchile.cl/~emenendez</a><div>
<br></div><div>Let's pray for the 33 trapped miners! Four months to rescue</div></span></span></div><div><span style="font-family: arial,sans-serif; font-size: 13px; border-collapse: collapse;"><blockquote type="cite">
<div><div class="gmail_quote"><div> </div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0px 0px 0px 0.8ex; padding-left: 1ex;">
<div><div style="font-family: 'times new roman','new york',times,serif; font-size: 12pt;"><div>---------- Mensaje reenviado ----------<div><br>From: Stefano Baroni <<a href="mailto:baroni@sissa.it" target="_blank">baroni@sissa.it</a>><br>
</div><div>
To: PWSCF Forum <<a href="mailto:pw_forum@pwscf.org" target="_blank">pw_forum@pwscf.org</a>><br></div>Date: Wed, 22 Sep 2010 19:43:15 +0200<div><br>Subject: Re: [Pw_forum] Young's Modulus<br></div><div>
<div>For that, also LRT akkows one to know what one is doing ... ;-)<div>
SB</div><div><br><div><div>On Sep 22, 2010, at 7:30 PM, Mehmet Topsakal wrote:</div><br><blockquote type="cite">Dear Eyvaz,<div><br></div><div>I think you omitted one more thing to mention. Brute-force method also allows one to know what he is doing.</div>
<div><br></div><div><br><br><div class="gmail_quote">On Wed, Sep 22, 2010 at 8:14 PM, Eyvaz Isaev <span dir="ltr"><<a href="mailto:eyvaz_isaev@yahoo.com" style="color: rgb(0, 0, 204);" target="_blank">eyvaz_isaev@yahoo.com</a>></span>wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0px 0px 0px 0.8ex; padding-left: 1ex;">
<div><div style="font-family: 'times new roman','new york',times,serif; font-size: 12pt;">Hi,<br><br>Yes, you are right about Abinit for elastic constants calculations. The main question is which method (Abinit or via total energy) is easier <br>
and less time-consuming. <br><div><br>Bests, <br><div>Eyvaz.</div>-------------------------------------------------------------------<br>Prof. Eyvaz Isaev, <br>Department of Physics, Chemistry, and Biology (IFM), Linkoping University, Sweden <br>
Theoretical Physics Department, Moscow State Institute of Steel & Alloys, Russia, <br><a href="mailto:isaev@ifm.liu.se" style="color: rgb(0, 0, 204);" target="_blank">isaev@ifm.liu.se</a>, <a href="mailto:eyvaz_isaev@yahoo.com" style="color: rgb(0, 0, 204);" target="_blank">eyvaz_isaev@yahoo.com</a></div>
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<div><div style="font-family: 'times new roman','new york',times,serif; font-size: 12pt;"><div><div><div><div><blockquote type="cite"><div><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0px 0px 0px 0.8ex; padding-left: 1ex;">
<div><div style="font-family: 'times new roman','new york',times,serif; font-size: 12pt;"><br></div></div></blockquote></div></div></blockquote></div></div></div></div></div></div></blockquote></div></div>
</div></span><br>-- <br><div><br></div><div><br></div><div>.</div><br>
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<br></div></blockquote></div><div><div></div><div class="h5"><br><br clear="all"><br>-- <br><div>Mohsen Modarresi, </div>
<div>PhD student of Solid State Physics, Ferdowsi University of Mashhad, Iran.<br>Phone +98-9133452131</div><br>
</div></div></blockquote></div><br><br clear="all"><br>-- <br><div>Mohsen Modarresi, </div>
<div>PhD student of Solid State Physics, Ferdowsi University of Mashhad, Iran.<br>Phone +98-9133452131</div><br>