<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">look at the two fitted equations of state (draw pictures) and see which one fits best the raw data<div>SB</div><div><br><div><div>On Sep 8, 2009, at 10:09 PM, udayagiri sai babu wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">Dear stefano baroni<br>I tried that as well i am getting the same value (255gpa). This is the data i am using<br><br>5.35 -174.156857800<br>5.36 -174.156934850<br>5.37 -174.156989300<br>5.38 -174.156990580<br>5.39 -174.156955990<br> 5.4 -174.156869280<br><br>this is one of the input file <br><br> &control<br>calculation = 'scf',<br>restart_mode='from_scratch',<br>outdir='/home/sai/temp',<br>prefix='chromium'<br> pseudo_dir='/home/sai/softwares/espresso-4.0.1/pseudo/',<br>tstress = .TRUE.,<br>tprnfor = .TRUE.,<br>/<br>&system<br>ibrav=3<br>celldm(1)=5.350000,<br>nat=1,<br>ntyp=1<br>ecutwfc=30,<br>ecutrho=300,<br>occupations='smearing',<br> smearing='mv',<br>degauss=0.012000<br>/<br>&electrons<br>conv_thr=1.D-8,<br>diagonalization='david',<br>mixing_mode='plain',<br>mixing_beta= 0.7<br>/<br>ATOMIC_SPECIES<br>Cr 51.9961 Cr.pw91-sp-van.UPF<br> ATOMIC_POSITIONS (crystal)<br>Cr 0.00000000 0.00000000 0.00000000<br>K_POINTS {automatic}<br>12 12 12 0 0 0<br><br>can you suggest me anything <br><br><div class="gmail_quote">On Wed, Sep 9, 2009 at 1:03 AM, Stefano Baroni <span dir="ltr"><<a href="mailto:baroni@sissa.it">baroni@sissa.it</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;"><div style="">How about trying to fit a very accurate set of data around the minimum with a parabola and calculate thus the bulk modulus? Have you tries to plot the resulting fitted curves? which one fits best the raw data? Udaygiri: in Science (as well as in Life) there is no free lunch ... Enjoy Science, no less than Life. SB<div> <br><div><div><div></div><div class="h5"><div>On Sep 8, 2009, at 9:04 PM, udayagiri sai babu wrote:</div><br></div></div><blockquote type="cite"><div><div></div><div class="h5"><br clear="all">hi all<br>i am using ev.x file given in the pw_tools directory to calculate bulk modulus and lattice parameter values of chromium. i used murnaghan equation of state to fit my data i got bulk modulus of 256 gpa where as my experimental value is 160 gpa but when i used keane equation of state to fit the same data i got 148 gpa bulk modulus <br> <br>why is this much variation? which equation of state should i use for cr? because for vanadium and Ti murnagan euation of state has given reasonable (<20% error) values of bulk modulus but not for Cr<br><br>please give some suggestions<br> -- <br>U.Saibabu<br>PhD student,<br>Deformation mechanisms modeling group,<br>Materials engineering department,<br>IISc Bangalore,<br>India.<br><br></div></div> _______________________________________________<br>Pw_forum mailing list<br> <a href="mailto:Pw_forum@pwscf.org" target="_blank">Pw_forum@pwscf.org</a><br><a href="http://www.democritos.it/mailman/listinfo/pw_forum" target="_blank">http://www.democritos.it/mailman/listinfo/pw_forum</a><br></blockquote> </div><br><div> <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; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;"><div 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; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;"><div 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; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;"><div 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; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;"><div 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; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;"><div style=""> <div><div style="margin: 0px;"><font size="3"><span style="font-size: 12px;">---</span></font></div><div style="margin: 0px;"><font size="3"><span style="font-size: 12px;">Stefano Baroni - SISSA</span></font><font size="3"><span style="font-size: 12px;"> </span></font><font size="3"><span style="font-size: 12px;">&</span></font><font size="3"><span style="font-size: 12px;"> </span></font><font size="3"><span style="font-size: 12px;">DEMOCRITOS National Simulation Center - Trieste</span></font></div> <div style="margin: 0px;"><font size="3"><span style="font-size: 12px;"><a href="http://stefano.baroni.me" target="_blank">http://stefano.baroni.me</a> [+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)</span></font></div> <div style="margin: 0px; min-height: 14px; font-size: 12px;"><br style="font-size: 12px;"></div><div style="margin: 0px; min-height: 14px; font-size: 12px;"><span style="font-size: 14px;"><div style="margin: 0px;"><font size="3"><span style="font-size: 12px;">La morale est une logique de l'action comme la logique est une morale de la pensée - Jean Piaget</span></font></div> <div style="margin: 0px;"><font size="3"><span style="font-size: 12px;"><br></span></font></div></span></div><div style="margin: 0px;"><font size="3"><span style="font-size: 12px;">Please, if possible, don't</span></font><font size="3"><span style="font-size: 12px;"> </span></font><font size="3"><span style="font-size: 12px;">send me MS Word or PowerPoint attachments</span></font></div> <div style="margin: 0px;"><font size="3"><span style="font-size: 12px;">Why? See:</span></font><font size="3"><span style="font-size: 12px;"> </span></font><font color="#0023e9" size="3"><span style="font-size: 12px;"><a href="http://www.gnu.org/philosophy/no-word-attachments.html" target="_blank">http://www.gnu.org/philosophy/no-word-attachments.html</a></span></font></div> <div><font color="#0023e9" size="3"><span style="font-size: 12px;"><br></span></font></div></div></div></span><br></div></span><br></div></span><br></div></span><br></div></span><br> </div><br></div></div><br>_______________________________________________<br> Pw_forum mailing list<br> <a href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br> <a href="http://www.democritos.it/mailman/listinfo/pw_forum" target="_blank">http://www.democritos.it/mailman/listinfo/pw_forum</a><br> <br></blockquote></div><br><br clear="all"><br>-- <br>U.Saibabu<br>PhD student,<br>Deformation mechanisms modeling group,<br>Materials engineering department,<br>IISc Bangalore,<br>India.<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 apple-content-edited="true"> <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; "><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-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: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><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-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: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><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-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: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><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-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: 0px; "><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; "><a href="http://stefano.baroni.me">http://stefano.baroni.me</a> [+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: normal normal normal 12px/normal Helvetica; min-height: 14px; font-size: 12px; "><span class="Apple-style-span" style="font-size: 14px; "><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; ">La morale est une logique de l'action comme la logique est une morale de la pensée - Jean Piaget</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; "><br></span></font></div></span></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></span><br class="Apple-interchange-newline"></div></span><br class="Apple-interchange-newline"></div></span><br class="Apple-interchange-newline"></div></span><br class="Apple-interchange-newline"> </div><br></div></body></html>