<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman,new york,times,serif;font-size:12pt"><div>Dear Manoj<br><br>i.e now in your input file the atomic position card will look like:<br>
<br>
ATOMIC POSITIONS<br>
Si 0 0 0 0 0 1<br>
Si 0.5 0.5 0.5 0 0 1<br>
Si 0.7 0.7 0.7 1 0 0<br>
<br>
This atomic position card allow you to displace first two atoms in z direction while the third Si in x direction. <br>
<br>
<br>
Regards<br>
Sagar Ambavale<br>
The M. S. University of Baroda<br>
India</div><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><div style="font-family: arial,helvetica,sans-serif; font-size: 10pt;">===============================<br><br><br>Message: 8<br>Date: Wed, 23 Sep 2009 17:50:22 -0400 (EDT)<br>From: Manoj Srivastava <<a ymailto="mailto:manoj@phys.ufl.edu" href="mailto:manoj@phys.ufl.edu">manoj@phys.ufl.edu</a>><br>Subject: [Pw_forum] relaxating only z coordinate?<br>To: PWSCF Forum <<a ymailto="mailto:pw_forum@pwscf.org" href="mailto:pw_forum@pwscf.org">pw_forum@pwscf.org</a>><br>Message-ID:<br> <<a ymailto="mailto:Pine.GSO.4.21.0909231745570.15412-100000@neptune.phys.ufl.edu" href="mailto:Pine.GSO.4.21.0909231745570.15412-100000@neptune.phys.ufl.edu">Pine.GSO.4.21.0909231745570.15412-100000@neptune.phys.ufl.edu</a>><br>Content-Type: TEXT/PLAIN; charset=US-ASCII<br><br>Dear PWSCF users, <br> This might have been answered previously, but I was
unable to find<br>it. How can one relax only z coordinate of atoms inside unit cell using<br>PW? In other words how can I constrain x and y coordinates of atoms during<br>relaxation?<br> <br><br>Regards, <br>Manoj Srivastava<br>University of Florida <br>Gainesville, FL <br><br><br><br>------------------------------<br><br>Message: 9<br>Date: Thu, 24 Sep 2009 06:29:11 +0800<br>From: lan haiping <<a ymailto="mailto:lanhaiping@gmail.com" href="mailto:lanhaiping@gmail.com">lanhaiping@gmail.com</a>><br>Subject: Re: [Pw_forum] relaxating only z coordinate?<br>To: PWSCF Forum <<a ymailto="mailto:pw_forum@pwscf.org" href="mailto:pw_forum@pwscf.org">pw_forum@pwscf.org</a>><br>Message-ID:<br> <<a ymailto="mailto:c92002fa0909231529v5070ed6yd2263af504c2dd61@mail.gmail.com" href="mailto:c92002fa0909231529v5070ed6yd2263af504c2dd61@mail.gmail.com">c92002fa0909231529v5070ed6yd2263af504c2dd61@mail.gmail.com</a>><br>Content-Type:
text/plain; charset="iso-8859-1"<br><br>Hi, Please check INPUT_PW document, you will find below description:<br>if_pos(1), if_pos(2), if_pos(3) INTEGER *Default:* 1<br><br>component i of the force for this atom is multiplied by if_pos(i),<br>which must be either 0 or 1. Used to keep selected atoms and/or<br>selected components fixed in meta-dynamics, neb, smd, MD dynamics or<br>structural optimization run.<br><br>If you want to fix some atom or some direction , just set if_pos(i) =0 .<br><br>Regards,<br><br>Hai-Ping<br><br><br><br><br></div></div></div><br>
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