<font face="Default Sans Serif,Verdana,Arial,Helvetica,sans-serif" size="2"><div>Dear Prof. Ghosh,<br><br>I should have done this before, but now I have performed structure relaxation of LiH..H2O using DFT with 6-31++g basis set,<br>the same one that was used for mp2 calculations, and found that DFT does not give intramolecular H-bond.<br>Thus, in general, DFT does not seem suitable for such systems and hence there has been difficulty with QE.<br><br>I agree with Paolo that the problem is not with plane wave approach.<br><br>Thanks once again and best regards,<br><br></div><div><font face="Default Sans Serif,Verdana,Arial,Helvetica,sans-serif" size="2"><div><font style="font-family: Georgia,Default Serif,serif; font-weight: bold;" color="#0000ff"><font color="#999900">Savita Pundlik</font></font><br style="font-family: Georgia,Default Serif,serif;"><span style="font-family: Georgia,Default Serif,serif;"><font><font color="#999900">Computational Materials </font></font></span><font color="#999900">Applied Research Group</font><br style="font-family: Georgia,Default Serif,serif;"><span style="font-family: Georgia,Default Serif,serif; font-weight: bold;"><font><font color="#999900">Computational Research Laboratories Ltd.,</font></font></span><br style="font-family: Georgia,Default Serif,serif;"><span style="font-style: italic; font-family: Georgia,Default Serif,serif;"><font><font color="#999900">Taco House, Damle Path, Off Law College Road</font></font></span><br style="font-style: italic; font-family: Georgia,Default Serif,serif;"><span style="font-style: italic; font-family: Georgia,Default Serif,serif;"><font><font color="#999900">Pune - 411004, India.</font></font></span><br><br></div></font><br><div><br></div><font color="#990099">-----pw_forum-bounces@pwscf.org wrote: -----<br><br></font><blockquote style="padding-right: 0px; padding-left: 5px; margin-left: 5px; border-left: 2px solid #000000; margin-right: 0px;">To: <a class="moz-txt-link-abbreviated" href="mailto:pw_forum@pwscf.org">pw_forum@pwscf.org</a><br>From: <a class="moz-txt-link-abbreviated" href="mailto:pw_forum-request@pwscf.org">pw_forum-request@pwscf.org</a><br>Sent by: <a class="moz-txt-link-abbreviated" href="mailto:pw_forum-bounces@pwscf.org">pw_forum-bounces@pwscf.org</a><br>Date: 06/20/2011 01:17PM<br>Subject: Pw_forum Digest, Vol 48, Issue 51<br><br><font face="Courier New,Courier,monospace" size="3">Send Pw_forum mailing list submissions to<br><span>&nbsp;&nbsp;&nbsp;&nbsp;</span>        <a class="moz-txt-link-abbreviated" href="mailto:pw_forum@pwscf.org">pw_forum@pwscf.org</a><br><br>To subscribe or unsubscribe via the World Wide Web, visit<br><span>&nbsp;&nbsp;&nbsp;&nbsp;</span>        <a href="http://www.democritos.it/mailman/listinfo/pw_forum">http://www.democritos.it/mailman/listinfo/pw_forum</a><br>or, via email, send a message with subject or body 'help' to<br><span>&nbsp;&nbsp;&nbsp;&nbsp;</span>        <a class="moz-txt-link-abbreviated" href="mailto:pw_forum-request@pwscf.org">pw_forum-request@pwscf.org</a><br><br>You can reach the person managing the list at<br><span>&nbsp;&nbsp;&nbsp;&nbsp;</span>        <a class="moz-txt-link-abbreviated" href="mailto:pw_forum-owner@pwscf.org">pw_forum-owner@pwscf.org</a><br><br>When replying, please edit your Subject line so it is more specific<br>than "Re: Contents of Pw_forum digest..."<br><br><br>Today's Topics:<br><br>&nbsp;&nbsp; 1. Re: Suitable pseudopotentials for LiH..H2O (Prasenjit Ghosh)<br>&nbsp;&nbsp; 2. Re: Testing pseudopotential (Julen Ibanez Azpiroz)<br><br><br>----------------------------------------------------------------------<br><br>Message: 1<br>Date: Mon, 20 Jun 2011 11:59:51 +0530<br>From: Prasenjit Ghosh <a class="moz-txt-link-rfc2396E" href="mailto:prasenjit.jnc@gmail.com">&lt;prasenjit.jnc@gmail.com&gt;</a><br>Subject: Re: [Pw_forum] Suitable pseudopotentials for LiH..H2O<br>To: PWSCF Forum <a class="moz-txt-link-rfc2396E" href="mailto:pw_forum@pwscf.org">&lt;pw_forum@pwscf.org&gt;</a><br>Message-ID: <a class="moz-txt-link-rfc2396E" href="mailto:BANLkTin0W8OO=H88_J38cxXnmWsMYT12rg@mail.gmail.com">&lt;BANLkTin0W8OO=H88_J38cxXnmWsMYT12rg@mail.gmail.com&gt;</a><br>Content-Type: text/plain; charset="iso-8859-1"<br><br>Dear Savita,<br><br>It is hard to tell....You can try plotting total energy vs. the box size and<br>see how the energies are changing....if the change is of the order of a meV<br>then I would say that your calculations are converged wrt box size.......<br><br>However, I think it is good idea to follow Stefano's suggestion........using<br>the same basis set you have been using for your mp2 calculation, you try to<br>calculate the same thing using DFT and see whether you get similar<br>results.....if you get different results, then it will suggest that DFT is<br>not properly describing the electronic correlations.<br><br>Prasenjit<br><br>On 20 June 2011 10:24, <a class="moz-txt-link-rfc2396E" href="mailto:psavita@crlindia.com">&lt;psavita@crlindia.com&gt;</a> wrote:<br><br>&gt; Dear Prof. Ghosh,<br>&gt;<br>&gt; As per your suggestion, I performed the structure relaxation of LiH--H2O<br>&gt; system using a bigger cubic box of dimension 50 a.u.<br>&gt; and I still find H2 abstraction instead of an intramolecular dihydrogen<br>&gt; bond.<br>&gt; Do you think the box is still inadequate?<br>&gt; For such systems, would it be better to put some constraints initially?<br>&gt; How do we do this in QE?<br>&gt;<br>&gt; Thanks for your suggestion and best regards,<br>&gt;<br>&gt; Savita Pundlik<br>&gt; Computational Materials Applied Research Group<br>&gt; Computational Research Laboratories Ltd.,<br>&gt; Taco House, Damle Path, Off Law College Road<br>&gt; Pune - 411004, India.<br>&gt;<br>&gt;<br>&gt;<br>&gt; -----pw_forum-bounces@pwscf.org wrote: -----<br>&gt;<br>&gt;<br>&gt;<br>&gt;<br>&gt;<br>&gt;<br>&gt; Dear Savita,<br>&gt;<br>&gt; I am not an expert on these type of systems.......however just a small<br>&gt; piece<br>&gt; of advice.....a single molecule of water has a huge dipole moment.....so a<br>&gt; box size of 25 bohr may not be sufficient, until and unless binding to LiH<br>&gt; quenches the dipole moment......so you may like to check whether your box<br>&gt; is<br>&gt; sufficiently big.....usually for a single molecule of water one uses about<br>&gt; 35-40 bohr box or can use dipole correction.<br>&gt;<br>&gt; Prasenjit<br>&gt;<br>&gt; On 17 June 2011 11:42, <a class="moz-txt-link-rfc2396E" href="mailto:psavita@crlindia.com">&lt;psavita@crlindia.com&gt;</a> <a class="moz-txt-link-rfc2396E" href="mailto:psavita@crlindia.com">&lt;psavita@crlindia.com&gt;</a>wrote:<br>&gt;<br>&gt; &gt; Hello,<br>&gt; &gt;<br>&gt; &gt; I have been trying to get the optimum structure of LiH..H2O that has an<br>&gt; &gt; intramolecular dihydrogen bond, using pwscf.<br>&gt; &gt; I could get the proper structure earlier using mp2 theory and 6-31++g<br>&gt; &gt; basis.<br>&gt; &gt;<br>&gt; &gt; For pwscf, the species is enclosed in a cubic box of 25 bohr for gamma<br>&gt; &gt; point calculation.<br>&gt; &gt; I tried the pz lda, pbe gga as well we blyp PS for the atoms in this<br>&gt; &gt; system, however, the first and the last<br>&gt; &gt; lead to H2O..LiH, the latter LiH being linear while pbe gives LiH + H2,<br>&gt; but<br>&gt; &gt; no dihydrogen bond. Is there any other PS<br>&gt;<br>&gt; &gt; that may lead to proper structure? Or is it that plane wave approach does<br>&gt; &gt; not suit systems of this kind?<br>&gt; &gt;<br>&gt; &gt; Thanks in advance and best regards,<br>&gt; &gt;<br>&gt; &gt; Savita Pundlik<br>&gt; &gt; Computational Materials Applied Research Group<br>&gt; &gt; Computational Research Laboratories Ltd.,<br>&gt; &gt; Taco House, Damle Path, Off Law College Road<br>&gt; &gt; Pune - 411004, India.<br>&gt; &gt;<br>&gt; &gt;<br>&gt; &gt;<br>&gt; &gt; _______________________________________________<br>&gt; &gt; Pw_forum mailing list<br>&gt; &gt; <a class="moz-txt-link-abbreviated" href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br>&gt; &gt; <a href="http://www.democritos.it/mailman/listinfo/pw_forum">http://www.democritos.it/mailman/listinfo/pw_forum</a><br>&gt; &gt;<br>&gt; &gt;<br>&gt;<br>&gt;<br>&gt; --<br>&gt; PRASENJIT GHOSH,<br>&gt; Assistant Professor,<br>&gt; IISER Pune,<br>&gt; First floor, Central Tower, Sai Trinity Building<br>&gt; Garware Circle, Sutarwadi, Pashan<br>&gt; Pune, Maharashtra 411021, India<br>&gt;<br>&gt; Phone: +91 (20) 2590 8203<br>&gt; Fax: +91 (20) 2589 9790<br>&gt; -------------- next part --------------<br>&gt; An HTML attachment was scrubbed...<br>&gt; URL:<br>&gt; <a href="http://www.democritos.it/pipermail/pw_forum/attachments/20110617/17d0a776/attachment-0001.htm">http://www.democritos.it/pipermail/pw_forum/attachments/20110617/17d0a776/attachment-0001.htm</a><br>&gt;<br>&gt;<br>&gt; ------------------------------<br>&gt;<br>&gt;<br>&gt; _______________________________________________<br>&gt; Pw_forum mailing list<br>&gt; <a class="moz-txt-link-abbreviated" href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br>&gt; <a href="http://www.democritos.it/mailman/listinfo/pw_forum">http://www.democritos.it/mailman/listinfo/pw_forum</a><br>&gt;<br>&gt;<br>&gt; End of Pw_forum Digest, Vol 48, Issue 45<br>&gt; ****************************************<br>&gt;<br>&gt;<br>&gt;<br>&gt; _______________________________________________<br>&gt; Pw_forum mailing list<br>&gt; <a class="moz-txt-link-abbreviated" href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br>&gt; <a href="http://www.democritos.it/mailman/listinfo/pw_forum">http://www.democritos.it/mailman/listinfo/pw_forum</a><br>&gt;<br>&gt;<br><br><br>-- <br>PRASENJIT GHOSH,<br>Assistant Professor,<br>IISER Pune,<br>First floor, Central Tower, Sai Trinity Building<br>Garware Circle, Sutarwadi, Pashan<br>Pune, Maharashtra 411021, India<br><br>Phone: +91 (20) 2590 8203<br>Fax: +91 (20) 2589 9790<br>-------------- next part --------------<br>An HTML attachment was sc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