<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 12 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:"Adobe Song Std L";
panose-1:0 0 0 0 0 0 0 0 0 0;}
@font-face
{font-family:"\@Adobe Song Std L";
panose-1:0 0 0 0 0 0 0 0 0 0;}
@font-face
{font-family:Candara;
panose-1:2 14 5 2 3 3 3 2 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
text-align:right;
direction:rtl;
unicode-bidi:embed;
font-size:11.0pt;
font-family:"Calibri","sans-serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 90.0pt 72.0pt 90.0pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>Hello dear users and developers,<o:p></o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><o:p> </o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>I'm trying to calculate the equation of state of Europium oxide, but I have some doubts regarding my procedure.<o:p></o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>I have the xyz coordinates of the unit cell in angstroms which I put into atom_positions and also define the needed celldm's().<o:p></o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><o:p> </o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>I'm interested to compress the material to different values (say, 0%, 10% and 20% volumetric compression) and calculate the total energy each time.<o:p></o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><o:p> </o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>Do I have to change the given initial xyz coordinates in atom_positions AND the celldm() , or just change the celldm() accordingly to the compression and pw.x will do the proper changes to the positions of the atoms ?<o:p></o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><o:p> </o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>I have done some calculations with uncompressed unit cell and with 20% compressed unit cell (by changing to the proper compressed celldm() values) but the difference in energy was about 0.5 Ry which i believe to be quite small. (Of course I checked previously for convergence).<o:p></o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><o:p> </o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>Am I doing it wrong ?<o:p></o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><o:p> </o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'>Any help will be greatly appreciated <o:p></o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><o:p> </o:p></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><b><span style='font-family:"Candara","sans-serif";color:#00B0F0'>David Furman, Graduate Student</span></b><span style='font-family:"Candara","sans-serif";color:#00B0F0'> </span><span style='font-size:10.0pt;font-family:"Candara","sans-serif";color:#00B0F0'>| Fritz Haber Research Center for <o:p></o:p></span></p><p class=MsoNormal style='text-align:left;direction:ltr;unicode-bidi:embed'><span style='font-size:10.0pt;font-family:"Candara","sans-serif";color:#00B0F0'>Molecular Dynamics</span><span style='font-family:"Candara","sans-serif";color:#00B0F0'>, </span><span style='font-size:10.0pt;font-family:"Candara","sans-serif";color:#00B0F0'>The Hebrew University of Jerusalem | </span><b><span style='font-family:"Candara","sans-serif";color:#00B0F0'>+972-8656-8909</span></b><b><o:p></o:p></b></p><p class=MsoNormal dir=RTL><span dir=LTR><o:p> </o:p></span></p></div></body></html>