<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>Il giorno 26/mag/2011, alle ore 01.00, Tram Bui ha scritto:</div><br class="Apple-interchange-newline"><blockquote type="cite">Dear Paul,<br> In the file that I have attached here (Paul's note on PP generation), under section 3.10: checking for transferability, you have mentioned about the:"The error on total energy differences<br>between PP and AE results gives a feeling on how good the PP is." Do you mean the difference in AE and PP eigenvalues? </blockquote><div><br></div><div>No, I think here Paolo "Paul" Giannozzi really meant what you understood first, but you didn't get it in the correct way.</div><div>You should really compare total energy differences, which means:</div><div>E_2(AE) - E_1(AE) versus E_2(PS) - E_1(PS)</div><div>where 1 and 2 label two different electronic configurations, and NOT</div><div>E_1(PS) versus E_1(AE) </div><div>as you are probably trying to do.</div><br><blockquote type="cite">because I saw the Etot and Etotps are huge difference </blockquote><div><br></div><div>This is often the case, given the high degree of freedom in the choice of PP parameters (especially for the local potential, I suppose).</div><div><br></div><blockquote type="cite">but their eigenvalue (e, Ry) are closed.<br></blockquote><div><br></div><div>Indeed this is how it should be, since the modern PP are designed to reproduce the scattering properties of the AE atomic potential as best as possible.</div><br><blockquote type="cite">
<br>Dear QE users,<br> I'm trying to test the Cs' US PP with reference configuration of :[Xe] 6s1 5d0 6p0. To test the PP, I'm using these five configuration (just by guessing): <br> configts(1)= '6s1 6p0 5d0'<br>
configts(2)= '6s0.5 6p0.5 5d0'<br> configts(3)= '6s0.5 6p0 5d0.5'<br> configts(4)= '6s0 6p1 5d0'<br> configts(5)= '6s0 6p0 5d1'<br>My questions are: <br> - how to choose the configurations for PP testing based on the reference one? is there a strategy or some sort?<br></blockquote><div><br></div><div>Use some reasonable configurations (remove or add one electron, or a fraction of it, move one or more electrons between different orbitals, ...).</div><div>The choice may also be driven by the class of materials that you are going to study (e.g. ionic crystals).</div><br><blockquote type="cite">
- how many configurations are enough for the test?<br></blockquote><div><br></div><div>That's up to you... 5 look enough for me. Don't forget to do some testing with the solid state code (e.g. bond distance of dimers, lattice constant of simple solids...).</div><div><br></div><div><br></div><div>HTH</div><div><br></div><div><br></div><div>GS</div><br><blockquote type="cite"><br>Thank you very much,<br> <br>Tram Bui<br><br>M.S. Materials Science & Engineering<br><a href="mailto:trambui@u.boisestate.edu" target="_blank">trambui@u.boisestate.edu</a><br>
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<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><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></span>
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