<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><br><div><div>On 05 Feb 2014, at 10:56, Ganjar Kurniawan <<a href="mailto:zargan88@yahoo.com">zargan88@yahoo.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div><div style="background-color: rgb(255, 255, 255); font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-size: 12pt;"><div>Dear QE<br></div><div style="font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><br></div><div style="font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;">I am trying to compare the calculation of the Lithium bulk system which has BCC structure with lattice constant is 6.597 bohr using different pseudopotential between Li.pbe-s-rrkjus_psl.0.2.1.UPF and Li.pw91-n-van.UPF.</div><div><br></div><div style="font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;">the result give different of total energy are -14.82521305 Ry and -1.82426227 Ry respectively...</div><div style="font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><br></div><div style="font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;">The question is why this is happen??? anyone can to explain it???</div><div style="font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><br></div><div style="font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;">the response very appreciated</div><div style="font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><br></div><div style="font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;">Best regard</div><div style="font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><br></div><div style="font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;">Ganjar Kurniawan S<br></div><div style="font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><br></div></div></div><span><lidoang.in></span><span><lidoang_vcrelax.out></span><span><lidoang_vcrelax2.out></span>_______________________________________________<br>Pw_forum mailing list<br><a href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br>http://pwscf.org/mailman/listinfo/pw_forum</blockquote></div><div><br></div><div><br></div><div>Usually, you should worry in the case two different pseudo potentials gave you the same total energy.</div><div>Indeed, the total energy is totally meaningless in a plane-wave calculation, the only physically meaningful</div><div>quantities being total energy differences.</div><div><br></div><div>This being said, in the specific case of yours Li pseudo potentials, it seems (after carefully looking inside to either</div><div>your *.out files or to the pseudo potential files), while one of the two pseudos just contains the 2s electron in the valence</div><div>(Zval=1.0), the other also contains also the two 1s electrons (Zval=3.0). So, in one case also the “core” electron contribution</div><div>to the total energy is included.</div><div><br></div><div>Moreover, just in the Li.pbe-s-rrkjus_psl.0.2.1.UPF file, you can read:</div><div><div> Suggested minimum cutoff for wavefunctions: 78. Ry</div><div> Suggested minimum cutoff for charge density: 355. Ry</div></div><div><br></div><div>Such a high value of the suggested cutoff (despite the pseudo is US), is likely toy be due just to the correct treatment</div><div>of the two (much more localised) core electrons).</div><div><br></div><div>Hope this helps,</div><div><br></div><div> Giovanni</div><div><br></div><div apple-content-edited="true">
-- <br><br>Giovanni Cantele, PhD<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<br>e-mail: <a href="mailto:giovanni.cantele@spin.cnr.it">giovanni.cantele@spin.cnr.it</a><br>Phone: +39 081 676910<br>Skype contact: giocan74<br><br>ResearcherID: <a href="http://www.researcherid.com/rid/A-1951-2009">http://www.researcherid.com/rid/A-1951-2009</a><br>Web page: <a href="http://people.na.infn.it/~cantele">http://people.na.infn.it/~cantele</a><br>
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