<div dir="ltr">We are slowly updating our ATOMPAW webpage <a href="http://pwpaw.wfu.edu">http://pwpaw.wfu.edu</a> to include LDA and PBESOL PAW datasets that are more reliable when used with Quantum Espresso. I just added Ca and could add more as needed. Of course, although similar datasets have been used in the past, the new ones always need to be tested. <div><br clear="all"><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature">N. A. W. Holzwarth email: <a href="mailto:natalie@wfu.edu" target="_blank">natalie@wfu.edu</a><div>Department of Physics web: <a href="http://www.wfu.edu/~natalie" target="_blank">http://www.wfu.edu/~natalie</a></div><div>Wake Forest University phone: 1-336-758-5510 </div><div>Winston-Salem, NC 27109 USA office: Rm. 300 Olin Physical Lab</div></div></div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, May 4, 2019 at 12:27 AM Yeon, Jejoon <<a href="mailto:jyeon@udel.edu">jyeon@udel.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div dir="ltr">
<div id="gmail-m_2060053796387749700divtagdefaultwrapper" style="font-size:12pt;color:rgb(0,0,0);font-family:Calibri,Helvetica,sans-serif" dir="ltr">
<p style="margin-top:0px;margin-bottom:0px">Hello </p>
<p style="margin-top:0px;margin-bottom:0px"><br>
</p>
<p style="margin-top:0px;margin-bottom:0px">I ran several DFTs few times before, but I only have limited amount of knowledge and experience in DFTs. </p>
<p style="margin-top:0px;margin-bottom:0px"><br>
</p>
<p style="margin-top:0px;margin-bottom:0px">I have Pyrope (Mg3Al2Si3O12) and Grossular (Ca<span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px">3Al2Si3O12)
unit cell, and wish to preform relax and vc-relax. </span><span style="font-size:12pt">After I get the relaxed atomic structure and cell size, I wish to make an energy curve of Pyrope / Grossular structure w.r.t. compression and expansion of volume, </span><span style="font-size:12pt">using
expanded / compressed </span><span style="font-size:12pt">unit cells</span><span style="font-size:12pt">. </span><span style="font-size:12pt">Purpose of this DFT is to get the database for the parametrization of empirical force field, especially for
mechanical properties like stress-strain curve and elastic constants. </span></p>
<p style="margin-top:0px;margin-bottom:0px"><span style="font-size:12pt"></span></p>
<p style="margin-top:0px;margin-bottom:0px"><span style="font-size:12pt"><br>
</span></p>
<p style="margin-top:0px;margin-bottom:0px">Now, I have PBE-PAW(kjpaw) and PBESOL-PAW(kjpaw) PPs for all atom types. I have no problem about Pyrope, I can run it with PBESOL. But Grossular is an issue. <span style="font-size:12pt">F</span><span style="font-size:12pt">or </span><span style="font-size:12pt">Ca, </span><span style="font-size:12pt">PBE
is only available option from QE PP webpage, there is no PBESOL for Ca yet</span><span style="font-size:12pt">. Accordingly, if I want to calculate energies of Grossular structure, I have
</span><span style="font-size:12pt">three </span><span style="font-size:12pt">options as far as I know: </span></p>
<p style="margin-top:0px;margin-bottom:0px">1) input_dft = 'PBE', while mix the PBE (Ca) and PBESOL (Al, Si, O) </p>
<p style="margin-top:0px;margin-bottom:0px">2) inout_dft = 'PBESOL'<span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px">,
while mix the PBE (Ca) and PBESOL (Al, Si, O)</span> </p>
<p style="margin-top:0px;margin-bottom:0px">3) just use PBE PPs for all 4 atom types. </p>
<p style="margin-top:0px;margin-bottom:0px"> </p>
<p style="margin-top:0px;margin-bottom:0px"><span style="font-size:12pt"></span></p>
<p style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px">
At this point, I'm not sure what would be the good choice for my purpose. <span style="font-size:12pt">I wish to use PBESOL because it is known to have better prediction for solid properties. But I'm not sure if I can mix them with PBE, and if I mix, which
input_dft option should I need to choose. </span></p>
<p></p>
<p style="margin-top:0px;margin-bottom:0px"><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px"><br>
</span></p>
<p style="margin-top:0px;margin-bottom:0px"><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px">I ran test relaxations for
3 cases, and </span><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px">I found that the </span><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px">final
atom coordinates of all 3 cases are very similar, they are mostly </span><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px">the
same up to </span><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px">second</span><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px"> decimal
point numbers. Their final optimized </span><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px">energies are different,
but as far as I know I can't compare them, isn't it? I'm not sure on which criteria should I need compare and select the best one from those three </span>options.<br>
</p>
<p style="margin-top:0px;margin-bottom:0px"><br>
</p>
<p style="margin-top:0px;margin-bottom:0px">Or, if anyone had a similar experience, I welcome any advises or suggestions. </p>
<p style="margin-top:0px;margin-bottom:0px"><br>
</p>
<p style="margin-top:0px;margin-bottom:0px">Just in case, following is my example in file. </p>
<p style="margin-top:0px;margin-bottom:0px"><br>
</p>
<p style="margin-top:0px;margin-bottom:0px"></p>
<div>&CONTROL</div>
<div> prefix="03_Relax_Grossular_80_800_PBESOL",</div>
<div> calculation='relax',</div>
<div> outdir="/scratch/jj/20190501_QEDFT_Grossular_EoS/03_Relax_Grossular_80_800_PBESOL/tmp",</div>
<div> pseudo_dir="/home/QE_pseudo/",</div>
<div> restart_mode= 'from_scratch',</div>
<div> nstep = 1000</div>
<div>/</div>
<div><br>
</div>
<div>&SYSTEM</div>
<div> ibrav=0,</div>
<div> nat=20,</div>
<div> ntyp=4,</div>
<div> ecutwfc=80,</div>
<div> ecutrho=800,</div>
<div> occupations='smearing',</div>
<div> smearing='methfessel-paxton',</div>
<div> degauss=0.005000,</div>
<div> input_dft='PBESOL'</div>
<div>/</div>
<div><br>
</div>
<div>&ELECTRONS</div>
<div> diagonalization='cg',</div>
<div> conv_thr=1d-07,</div>
<div> mixing_mode='plain',</div>
<div> mixing_beta=0.100,</div>
<div>/</div>
<div><br>
</div>
<div>&IONS</div>
<div> ion_dynamics = 'bfgs',</div>
<div>/</div>
<div><br>
</div>
<div>ATOMIC_SPECIES</div>
<div> Ca 40.078000 Ca.pbe-spn-kjpaw_psl.1.0.0.UPF</div>
<div> Al 26.981539 Al.pbesol-n-kjpaw_psl.1.0.0.UPF</div>
<div> Si 28.085500 Si.pbesol-n-kjpaw_psl.1.0.0.UPF</div>
<div> O 15.999400 O.pbesol-n-kjpaw_psl.1.0.0.UPF</div>
<div><br>
</div>
<div>ATOMIC_POSITIONS {angstrom}</div>
<div>Ca 1.480750 0.000000 2.961500</div>
<div>Ca 2.961500 1.480750 0.000000</div>
<div>Ca 0.000000 2.961500 1.480750</div>
<div>Al 0.000000 0.000000 0.000000</div>
<div>Al 2.961500 2.961500 2.961500</div>
<div>Si 0.000000 2.961500 4.442250</div>
<div>Si 4.442250 0.000000 2.961500</div>
<div>Si 2.961500 4.442250 0.000000</div>
<div>O 0.450148 5.393484 1.791116</div>
<div>O 1.791116 0.450148 5.393484</div>
<div>O 5.393484 1.791116 0.450148</div>
<div>O 3.491016 2.511352 4.752616</div>
<div>O 2.511352 4.752616 3.491016</div>
<div>O 4.752616 3.491016 2.511352</div>
<div>O 5.472852 0.529516 4.131885</div>
<div>O 4.131885 5.472852 0.529516</div>
<div>O 0.529516 4.131885 5.472852</div>
<div>O 2.431984 3.411648 1.170385</div>
<div>O 3.411648 1.170385 2.431984</div>
<div>O 1.170385 2.431984 3.411648</div>
<div><br>
</div>
<div>K_POINTS {automatic}</div>
<div> 4 4 4 0 0 0</div>
<div><br>
</div>
<div>CELL_PARAMETERS {angstrom}</div>
<div> 5.923000000 0.000000000 0.000000000</div>
<div> 0.000000000 5.923000000 0.000000000</div>
<div> 0.000000000 0.000000000 5.923000000</div>
<br>
<p></p>
<p style="margin-top:0px;margin-bottom:0px">Thank you </p>
<p style="margin-top:0px;margin-bottom:0px"><br>
</p>
<p style="margin-top:0px;margin-bottom:0px"><br>
</p>
</div>
</div>
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