<div dir="ltr">Thanks Stefano;<div><br></div><div>But, what do you mean by "some"? I am interested specifically in Fe at high pressure, so, can QE do 3rd derivative for that?</div><div><br></div><div><div style="font-size:12.8px">Here</div><div style="font-size:12.8px"><div style="font-size:small"><span style="font-size:12.8px"><br></span></div><div style="font-size:small"><span style="font-size:12.8px"><a href="http://www.quantum-espresso.org/wp-content/uploads/Doc/ph_user_guide.pdf" target="_blank">http://www.quantum-espresso.org/wp-content/uploads/Doc/ph_user_guide.pdf</a></span><br></div><div><br></div></div><div style="font-size:12.8px">it says</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">"D3/d3.x: calculates anharmonic phonon lifetimes (third-order derivatives of the energy), using data produced by pw.x and ph.x (USPP and PAW not supported)."<br></div></div><div><br></div><div>So, it looks like it is NCPP.</div><div><br></div><div>Thanks;</div><div>Sabry</div><div><br></div><div><br></div></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature"><div dir="ltr"><span>==================================================<span><br></span><span>Sabry</span> G. <span>Moustafa</span>, Ph.D.<br>Department of Chemical and Biological Engineering<br><span>511</span> <span>Furnas</span> <span>Hall</span><br>University at Buffalo, The State University of New York<br>Buffalo, NY 14260-4200<br>716-645-1186 (office)<br>716-239-8543 (cell)<span style="border-collapse:separate;border-spacing:0px"><div style="word-wrap:break-word"><span style="border-collapse:separate;border-spacing:0px"><div style="word-wrap:break-word"><span style="border-collapse:separate;border-spacing:0px"><div style="word-wrap:break-word"><div style="color:rgb(0,0,0);font-size:12.8px"><span style="font-size:12.8px">E-mail: </span><a href="mailto:kofke@buffalo.edu" style="font-size:12.8px" target="_blank">sabrygad@buffalo.edu</a></div></div></span></div></span></div></span></span></div></div></div>
<br><div class="gmail_quote">On Wed, Apr 20, 2016 at 12:28 AM, stefano de gironcoli <span dir="ltr"><<a href="mailto:degironc@sissa.it" target="_blank">degironc@sissa.it</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<div>the phonon code evaluates second order
derivatives (dynamical matrices).<br>
this is available for NCPP, USPP and PAW<br>
<br>
the D3 code computes some of the third order derivatives.<br>
it is working for NCPP only as far as I remember.<br>
<br>
forth order derivatives are not computed.<br>
<br>
stefano<div><div class="h5"><br>
<br>
On 20/04/2016 06:34, Sabry Gad Al Hak Moustafa wrote:<br>
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<blockquote type="cite"><div><div class="h5">
<div dir="ltr">
<div><span style="font-size:12.8px">Hi;</span>
<div style="font-size:12.8px"><br>
<div>Was wondering if QE can compute 2nd, 3rd and 4th energy
derivatives in the DFPT framework? If so, is available in
PAW, or just PPs?</div>
<div><br>
</div>
<div>Thanks;</div>
<div>Sabry</div>
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<div dir="ltr"><span>==================================================<span><br>
</span><span>Sabry</span> G. <span>Moustafa</span>,
Ph.D.<br>
Department of Chemical and Biological Engineering<br>
<span>511</span> <span>Furnas</span> <span>Hall</span><br>
University at Buffalo, The State University of New York<br>
Buffalo, NY 14260-4200<br>
716-645-1186 (office)<br>
716-239-8543 (cell)<span style="border-collapse:separate;border-spacing:0px">
<div style="word-wrap:break-word"><span style="border-collapse:separate;border-spacing:0px">
<div style="word-wrap:break-word"><span style="border-collapse:separate;border-spacing:0px">
<div style="word-wrap:break-word">
<div style="color:rgb(0,0,0);font-size:12.8px"><span style="font-size:12.8px">E-mail: </span><a href="mailto:kofke@buffalo.edu" style="font-size:12.8px" target="_blank"></a><a href="mailto:sabrygad@buffalo.edu" target="_blank">sabrygad@buffalo.edu</a></div>
</div>
</span></div>
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</span></span></div>
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