<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">atomic relaxation is allowed in any directions. when some components of the forces vanish exactly, this occurs because of symmetry reasons. SB<div><br><div><html>On Mar 26, 2008, at 7:14 PM, Jun Dai wrote:</html><br class="Apple-interchange-newline"><blockquote type="cite">Dear PWSCF users,<br>i found the forces acting on atoms in the output of the relax examples in<br>cvs-version(~/espresso4.0cvs/tests/relax2.out for example) go as follows:<br><br> Forces acting on atoms (Ry/au):<br><br> atom 1 type 1 force = 0.00000000 0.00000000 0.01010485<br> atom 2 type 1 force = 0.00000000 0.00000000 -0.00112292<br> atom 3 type 1 force = 0.00000000 0.00000000 0.00257324<br> atom 4 type 1 force = 0.00000000 0.00000000 0.00000000<br> atom 5 type 1 force = 0.00000000 0.00000000 -0.00257324<br> atom 6 type 1 force = 0.00000000 0.00000000 0.00112292<br> atom 7 type 1 force = 0.00000000 0.00000000 -0.01010485<br><br>only forces on z-direction are there, i think maybe relax atoms in all directions<br>is more reasonable, is this situation a particular one or a common one?<br><br><br><br><br>------------------------------<br>Best regards,<br>Jun Dai<br><br>=============================================================<br> J. Dai<br> Ph.D. Candidate,<br> Hefei National Laboratory For Physical Sciences at the Microscale,<br> University of Science and Technology of China,<br> Hefei, Anhui, 230026,<br> People's Republic of China<br> Tel.: 86-551-3606428<br> Fax.: 86-551-3602969<br> E-mail: <a href="mailto:jdai3@mail.ustc.edu.cn">jdai3@mail.ustc.edu.cn</a><br>=============================================================<br>_______________________________________________<br>Pw_forum mailing list<br><a href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br>http://www.democritos.it/mailman/listinfo/pw_forum<br></blockquote></div><br><div> <span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; ">---</span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; ">Stefano Baroni - SISSA</span></font><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; "> </span></font><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; ">&</span></font><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; "> </span></font><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; ">DEMOCRITOS National Simulation Center - Trieste</span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; ">[+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)</span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; font-size: 12px; "><br style="font-size: 12px; "></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; ">Please, if possible, don't</span></font><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; "> </span></font><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; ">send me MS Word or PowerPoint attachments</span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; ">Why? See:</span></font><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; "> </span></font><font class="Apple-style-span" color="#0023E9" size="3"><span class="Apple-style-span" style="font-size: 12px; "><a href="http://www.gnu.org/philosophy/no-word-attachments.html">http://www.gnu.org/philosophy/no-word-attachments.html</a></span></font></div><div><font class="Apple-style-span" color="#0023E9" size="3"><span class="Apple-style-span" style="font-size: 12px; "><br class="webkit-block-placeholder"></span></font></div></div></div></span><br class="Apple-interchange-newline"> </div><br></div></body></html>