Dear Elie, <br><br>In case you are interested in isolated systems, not crystals, and if you are trying to visually choose a cell that has the minimum volume with adequate vacuum, apart from XCRYSDEN + playing with pwscf input solution you can also use the free (but not open source) editor DSVIEWER by Accelrys. <br>
<br><a href="http://accelrys.com/products/discovery-studio/visualization-download.php">http://accelrys.com/products/discovery-studio/visualization-download.php</a><br><br>I use it to draw initial structures, to play with the periodic cell, and align coordinates with respect to the cell. The program does not have any means to export PWSCF input. I export the structure in XYZ format, which is a text file that can be directly used in PWSCF in "angstrom" coordinate mode when first two lines are removed, and I edit the cell dimensions using the values I depicted by hand. <br>
<br>By the way, I would be glad if someone can point me an open source alternative which has extensive editing/monitoring capabilites for isolated systems like this one, and stable at the same time. <br><br>Best,<br>Baris<br>
<br><br><br><div class="gmail_quote">2010/3/10 mohnish pandey <span dir="ltr"><<a href="mailto:mohnish.iitk@gmail.com">mohnish.iitk@gmail.com</a>></span><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Dear Elie,<div> I you have to give the celldm's initially. You can get the experimental value from literatures and use that as initial value. Then you can do "vc-relax" calculation to get equilibrium values of cell parameters computationally. Of course it will be different from experimental value. GGA calculation overestimates the value while LDA calculation underestimates the lattice parameter.</div>
<div>Regards,</div><div>MOHNISH </div><div><br><div class="gmail_quote"><div><div></div><div class="h5">On Wed, Mar 10, 2010 at 1:20 AM, Elie Moujaes <span dir="ltr"><<a href="mailto:elie.moujaes@hotmail.co.uk" target="_blank">elie.moujaes@hotmail.co.uk</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">
<div>
Is there a way (maybe a free software or program) to get celldim (i) (i=1,...6) before giving it as an input in the calculations?<div><br>
<br>
Regards<br>
<br>
Elie Moujaes<br>
University of Nottingham<br>
NG7 2RD<br>
UK<br>
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<br></div></blockquote></div><br><br clear="all"><br>-- <br>Mohnish Pandey<br>Y6927262,4th Year dual degree student,<br>Department of Chemical Engineering,<br>IIT KANPUR<br>09235721300<br>
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