<div dir="ltr"><div>Dear Dr.
<span style="color:rgb(0,0,0);letter-spacing:normal;text-transform:none;white-space:normal;word-spacing:0px">Giovanni Cantele<br></span></div><div><br></div><div>Thank you very much for this helpful information.</div><div><br></div><div>After modifying the input, I found that the choice of <b>eopreg </b>also affects the result.</div><div>I found the dipole value close to zero using the attached input, but I still don't know how to chose the value of the
<b>eopreg. Would you mind to give me some more explanation on the
<b>eopreg</b>?</b></div><div><b><br></b></div><div>With Regards<b><br> </b>
</div><div><span style="color:rgb(0,0,0);letter-spacing:normal;text-transform:none;white-space:normal;word-spacing:0px"></span></div>
<br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, May 26, 2020 at 6:15 AM Giovanni Cantele <<a href="mailto:giovanni.cantele@spin.cnr.it">giovanni.cantele@spin.cnr.it</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 style="overflow-wrap: break-word;">An issue with your input is that you place the point where the external saw-tooth potential<div>has a discontinuity in its derivative at emaxpos = 0.5 (it is in crystal units, so because edir = 3,</div><div>it means that the potential depends on z and the discontinuity is at (0,0,a/2)).</div><div>However, the CO2 molecule is placed along the x axis at fixed y = a/2 and z = a/2. As such,</div><div>the discontinuity, which is unphysical since in serves to compensate the spurious dipole field that</div><div>would arise as a consequence of the periodic boundary conditions, is located in a region where the</div><div>charge density is not zero. emaxpos should be set in such a way that the discontinuity il located</div><div>in the vacuum, in the region where the charge density is zero or in any case very small. In your setup</div><div>it seems that a good choice would be emaxpos=0.</div><div><br></div><div>Giovanni</div><div><br></div><div>PS since you’re studying an isolated molecule, provided the size of your supercell is sufficiently large,</div><div>the eigenvalues should exhibit no dependence on k. As a consequence, in this case, a 4x4x4 sampling</div><div>of the Brillouin zone, should provide results equivalent to a gamma only sampling. So, you can switch to</div><div>KPOINTS automatic</div><div>1 1 1 0 0 0</div><div>or, even better,</div><div>KPOINTS gamma</div><div>to make your calculation faster while keeping the same accuracy.<br><div><br><blockquote type="cite"><div>On 27 May 2020, at 03:42, ENDALE ABEBE <<a href="mailto:endtse@gmail.com" target="_blank">endtse@gmail.com</a>> wrote:</div><br><div><div dir="ltr"><div>Dear Experts, users and all</div><div><br></div><div>
<div><span><div style="padding-right:0px"><span><div>I found the dipoles of CO2 calculated by Quantum ESPRESSO as :</div><div><br></div><div> Computed dipole along edir(3) :
</div><div> Elec. dipole 0.3112 Ry au, 0.7909 Debye</div><div> Ion. dipole 0.8137 Ry au, 2.0683 Debye</div><div> Dipole 41.9812 Ry au, 106.7055 Debye</div><div> Dipole field 0.5025 Ry au, <br></div><div><br></div><div>I assumed the third value is the sum of the electronic and ionic contributions.</div><div>The input and output files are attached herewith. </div><div>Since CO2 is non-polar molecule (with polar bonds), shouldn't the total dipole moment be zero?</div></span></div></span></div>
</div><div><br>-- <br><div dir="ltr"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><span style="color:rgb(153,153,153)"><span style="background-color:rgb(0,0,0)"><span></span></span><span style="color:rgb(0,0,255)">Endale Abebe</span></span></div><div><span style="color:rgb(0,0,255)">Program coordinator and </span><span style="color:rgb(0,0,255)"><span><span style="color:rgb(0,0,255)">Lecturer</span></span></span></div><div><span style="color:rgb(0,0,255)">Faculty of Materials Science and Engineering</span></div><div><span style="color:rgb(0,0,255)">Jimma Institute of Technology</span></div><div><span style="color:rgb(0,0,255)">Jimma University<br></span></div><div><span style="color:rgb(0,0,255)">P.O.Box 378, Jimma, Ethiopia</span></div><div><span style="color:rgb(0,0,255)">Mobile: +251921381598</span><br></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div>
<span id="gmail-m_-9048047601021404206cid:f_kaoooz1y0"><CO2_nscf.out></span><span id="gmail-m_-9048047601021404206cid:f_kaoooz281"><CO2_nscf.in></span>_______________________________________________<br>Quantum ESPRESSO is supported by MaX (<a href="http://www.max-centre.eu/quantum-espresso" target="_blank">www.max-centre.eu/quantum-espresso</a>)<br>users mailing list <a href="mailto:users@lists.quantum-espresso.org" target="_blank">users@lists.quantum-espresso.org</a><br><a href="https://lists.quantum-espresso.org/mailman/listinfo/users" target="_blank">https://lists.quantum-espresso.org/mailman/listinfo/users</a></div></blockquote></div><br><div>
<div dir="auto" style="color:rgb(0,0,0);letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none"><div dir="auto" style="color:rgb(0,0,0);letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none"><div style="text-align:start;text-indent:0px"><div style="text-align:start;text-indent:0px"><span style="color:rgb(0,0,0);letter-spacing:normal;text-transform:none;white-space:normal;word-spacing:0px">-- <br><br>Giovanni Cantele, PhD</span></div><div style="text-align:start;text-indent:0px"><span style="color:rgb(0,0,0);letter-spacing:normal;text-transform:none;white-space:normal;word-spacing:0px"><br>CNR-SPIN<br>c/o Dipartimento di Fisica<br>Universita' di Napoli "Federico II"<br>Complesso Universitario M. S. Angelo - Ed. 6<br>Via Cintia, I-80126, Napoli, Italy</span></div><div style="text-align:start;text-indent:0px"><span style="color:rgb(0,0,0);letter-spacing:normal;text-transform:none;white-space:normal;word-spacing:0px"><br><a href="mailto:giovanni.cantele@spin.cnr.it" target="_blank">e-mail: giovanni.cantele@spin.cnr.it</a></span></div><div style="text-align:start;text-indent:0px"><span style="color:rgb(0,0,0);letter-spacing:normal;text-transform:none;white-space:normal;word-spacing:0px"> <a href="mailto:gcantele@gmail.com" target="_blank">gcantele@gmail.com</a><br>Phone: +39 081 676910<br>Skype contact: giocan74<br>Web page:<span> </span></span><a href="https://sites.google.com/view/giovanni-cantele" target="_blank">https://sites.google.com/view/giovanni-cantele</a></div></div></div></div>
</div>
<br></div></div>_______________________________________________<br>
Quantum ESPRESSO is supported by MaX (<a href="http://www.max-centre.eu/quantum-espresso" rel="noreferrer" target="_blank">www.max-centre.eu/quantum-espresso</a>)<br>
users mailing list <a href="mailto:users@lists.quantum-espresso.org" target="_blank">users@lists.quantum-espresso.org</a><br>
<a href="https://lists.quantum-espresso.org/mailman/listinfo/users" rel="noreferrer" target="_blank">https://lists.quantum-espresso.org/mailman/listinfo/users</a></blockquote></div><br clear="all"><br>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><span style="color:rgb(153,153,153)"><span style="background-color:rgb(0,0,0)"><span></span></span><span style="color:rgb(0,0,255)">Endale Abebe</span></span></div><div><span style="color:rgb(0,0,255)">Program coordinator and </span><span style="color:rgb(0,0,255)"><span><span style="color:rgb(0,0,255)">Lecturer</span></span></span></div><div><span style="color:rgb(0,0,255)">Faculty of Materials Science and Engineering</span></div><div><span style="color:rgb(0,0,255)">Jimma Institute of Technology</span></div><div><span style="color:rgb(0,0,255)">Jimma University<br></span></div><div><span style="color:rgb(0,0,255)">P.O.Box 378, Jimma, Ethiopia</span></div><div><span style="color:rgb(0,0,255)">Mobile: +251921381598</span><br></div></div></div></div></div></div></div></div></div></div></div></div></div>