<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Dear Giuseppe,<div><br></div><div> I think your reply reached also the PW-forum, since I've received it twice, so everyone should have been able to read it.</div><div><br><div><div>Il giorno 23/mar/2011, alle ore 10.48, <a href="mailto:giuseppe.mattioli@mlib.ism.cnr.it">giuseppe.mattioli@mlib.ism.cnr.it</a> ha scritto:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Dear Gabriele<br><br><blockquote type="cite"> is there any concrete evidence that "ab initio" van der Waals <br></blockquote><blockquote type="cite">vdW-DF is systematically better than Grimme's vdW?<br></blockquote><br>Yes, at least in the case of molecule-surface interactions. </div></blockquote><div><br></div><div>Maybe graphite is another story... with PBE-D2 you should get an interlayer spacing just 3.4% smaller than the experimental value, which is not so bad considering the much larger PBE error.</div><div><br></div><br><blockquote type="cite"><div>There is a <br>recent (2010) Grimme paper (I'm sorry, I cannot be more accurate <br>today...) </div></blockquote><div><br></div><div>Maybe this one: </div><div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 9px/normal Times; color: rgb(26, 26, 24); font-size: 13px; ">THE JOURNAL OF CHEMICAL PHYSICS <b>132</b>, 154104 <font class="Apple-style-span" face="Helvetica">(</font>2010)</div></div>which is the paper introducing the D3 method (and a comparison with its predecessor D2)</div><div><br><blockquote type="cite"><div>that reports an overestimate of the above interactions when <br>using DFT-D2, currently implemented in QE. I've performed comparative <br>tests (classical MM, DFT-D2, vdW-DF) on several molecules interacting <br>with the non-polar 10-10 ZnO surface and I've obtained the best <br>results (some of them comparable with experimental data, i.e., the <br>thiophene ring) by using the vdW-DF approach. The DFT-D2 setup, <br>however, is quite good for molecules in my experience, and can be <br>tuned by changing the C6 coefficients by hand <br>(QE/Modules/mm_dispersion.f90), following one of the available force <br>fields (AMBER, CHARMM, ...).</div></blockquote><blockquote type="cite"><div>Maybe DFT-D3 and vdW-DF would converge to <br>similar results...<br></div></blockquote><div><br></div><div>I can't tell this, but I know that DFT-D3 should include some notable improvements with respect to the D2 version, since it now takes into account some kind of local coordination of the atoms, atom-pair specific coefficients (from ab initio), and should also separate better the long range regime from the short range one. I know there is someone who offered to look at implementing the extension to D3, maybe it will be available in a few months time.</div><br><blockquote type="cite"><div>What about cp?<br></div></blockquote><div><br></div>No clear idea here. However I believe it should not be difficult to port DFT-D2 to CP, since it requires only atomic positions and the cell setup. These should be handled in a similar way in PW and CP.</div><div><br></div><div><br></div><div>Gabriele</div><div><br><blockquote type="cite"><div><br>Yours<br><br>G.<br><br>Quoting Gabriele Sclauzero <<a href="mailto:sclauzer@sissa.it">sclauzer@sissa.it</a>>:<br><br><blockquote type="cite">Dear Giuseppe,<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"> is there any concrete evidence that "ab initio" van der Waals <br></blockquote><blockquote type="cite">vdW-DF is systematically better than Grimme's vdW?<br></blockquote><blockquote type="cite">Are you aware of any paper comparing the latest version of the two <br></blockquote><blockquote type="cite">methodologies (or "phisolophies", if you want), i.e. vdW-DF2 vs <br></blockquote><blockquote type="cite">DFT-D3?<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Cheers,<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">GS<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Il giorno 23/mar/2011, alle ore 10.12, <br></blockquote><blockquote type="cite"><a href="mailto:giuseppe.mattioli@mlib.ism.cnr.it">giuseppe.mattioli@mlib.ism.cnr.it</a> ha scritto:<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Dear all<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">You can do better than the semiempirical "Grimme" correction. There is<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">a new ab initio van der Waals correlation functional implemented in QE<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">4.3a. Try input_dft='vdW-DF', in the &sysytem list.<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">By the way, what about a (semiempirical or ab initio) vdW scheme in<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">cp.x? Is there any project going on?<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Yours<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Giuseppe<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Quoting Masoud Nahali <<a href="mailto:masoudnahali@gmail.com">masoudnahali@gmail.com</a>>:<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">Dear Eric<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">Try london="true" to get improved answer; as you should know DFT is weak<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">to calculate dispersion forces and by using the keyword one can include<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">these forces semi-empirically. I hope it helps.<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">Best Wishes<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">Masoud<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">--------------<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">Masoud Nahali, Sharif University of Technology<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">Eric Wrote:<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">Dear all,<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">I'm trying to optimize unit cell parameter of graphite.<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">The problem is the c axis gets too long.<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">Starting from published data my initial parameters are a=4.59203 Bohr<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">and c=12.513 Bohr.<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">The final values are 4.664 and 15.829 respectively.<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">I need someone to explain to me what I did wrong, I've attached my input<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">file.<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">That's a basic calculation so it's very frustrating to not make it done.<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">I thank you in advance,<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"> Eric.<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">--<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">/Be the change you wish to see in the world<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">/ --- Mahatma Gandhi ---<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">Dr. Éric Germaneau <mailto:germaneau at <a href="http://gucas.ac.cn">gucas.ac.cn</a><br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><<a href="http://www.democritos.it/mailman/listinfo/pw_forum">http://www.democritos.it/mailman/listinfo/pw_forum</a>>><br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">College of Physical Sciences<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">Graduate University of Chinese Academy of Sciences<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">Yuquan Road 19A<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">Beijing 100049<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">China<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Giuseppe Mattioli<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">ISM-CNR<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Italy<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">_______________________________________________<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Pw_forum mailing list<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><a href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><a href="http://www.democritos.it/mailman/listinfo/pw_forum">http://www.democritos.it/mailman/listinfo/pw_forum</a><br></blockquote></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">§ Gabriele Sclauzero, EPFL SB ITP CSEA<br></blockquote><blockquote type="cite"> PH H2 462, Station 3, CH-1015 Lausanne<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><br><br><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></div></blockquote></div><br><div>
<div><span class="Apple-style-span" style="color: rgb(126, 126, 126); font-size: 16px; font-style: italic; "><br class="Apple-interchange-newline">§ Gabriele Sclauzero, EPFL SB ITP CSEA</span></div><div><font class="Apple-style-span" color="#7E7E7E"><i> PH H2 462, Station 3, CH-1015 Lausanne</i></font></div>
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