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<P style="MARGIN: 0in 0in 0pt" class=MsoNormal>Ciao Tutti (especially Paolo,
Mateo etc.),<o:p></o:p></P>
<P style="MARGIN: 0in 0in 0pt" class=MsoNormal><o:p> </o:p></P>
<P style="MARGIN: 0in 0in 0pt" class=MsoNormal>OK, I’ve been away for a while,
busy with energy issues and trying to understand why Alex Mueller may have been
on the right track wrt to explaining why high temperature superconductivity
manifests in the copper oxide perovskites. PW_FORUM is not the right place
to “advertize” one’s publications, but I owe much to the QE community and its
creators and contributors. Contact me if you’re interested in further
info.<o:p></o:p></P>
<P style="MARGIN: 0in 0in 0pt" class=MsoNormal><o:p> </o:p></P>
<P style="MARGIN: 0in 0in 0pt" class=MsoNormal>The reason for this posting is as
follows:<o:p></o:p></P>
<P
style="TEXT-INDENT: -0.25in; MARGIN: 0in 0in 0pt 0.5in; mso-list: l0 level1 lfo1"
class=MsoListParagraph><SPAN style="mso-fareast-font-family: Calibri"><SPAN
style="mso-list: Ignore">(1)<SPAN
style="FONT: 7pt 'Times New Roman'"> </SPAN></SPAN></SPAN>I’d
like to investigate via QE-DFT the “properties” of several Pr, alkaline
earth-oxide perovskites, and thus need to have an appropiate Pr pseudopotential,
one that would be compatible with the PP library of QE.<o:p></o:p></P>
<P
style="TEXT-INDENT: -0.25in; MARGIN: 0in 0in 0pt 0.5in; mso-list: l0 level1 lfo1"
class=MsoListParagraph><SPAN style="mso-fareast-font-family: Calibri"><SPAN
style="mso-list: Ignore">(2)<SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></SPAN></SPAN>Browsing the QE, Vanderbilt, Opium, Haber and Martins sites
(US-PS, NC-PS), I could find “none” that were pregenerated.<o:p></o:p></P>
<P
style="TEXT-INDENT: -0.25in; MARGIN: 0in 0in 0pt 0.5in; mso-list: l0 level1 lfo1"
class=MsoListParagraph><SPAN style="mso-fareast-font-family: Calibri"><SPAN
style="mso-list: Ignore">(3)<SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></SPAN></SPAN>Therefore, I may be “on my own,” and would appreciate
advice:<o:p></o:p></P>
<P
style="TEXT-INDENT: -0.25in; MARGIN: 0in 0in 0pt 1in; mso-list: l0 level2 lfo1"
class=MsoListParagraph><SPAN style="mso-fareast-font-family: Calibri"><SPAN
style="mso-list: Ignore">a.<SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></SPAN></SPAN>Is the community aware of any suitable Pr PPs I could
obtain and use?<o:p></o:p></P>
<P
style="TEXT-INDENT: -0.25in; MARGIN: 0in 0in 0pt 1in; mso-list: l0 level2 lfo1"
class=MsoListParagraph><SPAN style="mso-fareast-font-family: Calibri"><SPAN
style="mso-list: Ignore">b.<SPAN
style="FONT: 7pt 'Times New Roman'">
</SPAN></SPAN></SPAN>If not, I’d appreciate advice on how to generate my own,
using either the “famous” ld1.x, or a suitable equivalent</P>
<P
style="TEXT-INDENT: -0.25in; MARGIN: 0in 0in 0pt 1in; mso-list: l0 level2 lfo1"
class=MsoListParagraph>c. Does anyone know about or use the
"Octopus" site (<A
title="http://www.tddft.org/programs/octopus
CTRL + Click to follow link"
href="http://www.tddft.org/programs/octopus">http://www.tddft.org/programs/octopus</A>)</P>
<P
style="TEXT-INDENT: -0.25in; MARGIN: 0in 0in 0pt 0.5in; mso-list: l0 level1 lfo1"
class=MsoListParagraph><SPAN style="mso-fareast-font-family: Calibri"><SPAN
style="mso-list: Ignore">(4)<SPAN
style="FONT: 7pt 'Times New Roman'"> </SPAN></SPAN></SPAN>Pr
is a particular pernicious element ([Xe] 4f3-6s2) . Simply put, it can be
either 3+ or 4+…or somewhere in between – the 4f states are known to hybidize
extensively. Studies I did at IBM on the Pr-1237 system indicated its
ground quantum state may be in some sort of “heavy fermion” configuration.
Think about it. Why is not Pr-1237 superconducting…or even metallic, even
though its crystal structure is nearly identical to Y-1237? That’s the
most unsolved mystery of 20<SUP>th</SUP> century condensed matter physics…next
to why the copper oxide perovskites are superconducting at all.<o:p></o:p></P>
<P style="MARGIN: 0in 0in 0pt" class=MsoNormal><o:p> </o:p></P>
<P style="MARGIN: 0in 0in 0pt" class=MsoNormal>Finally, I remind all of the
wisdom of David Vanderbilt’s remark, something to the effect, “Pseudopotential
generation is a black art.”<o:p></o:p></P>
<P style="MARGIN: 0in 0in 0pt" class=MsoNormal><o:p> </o:p></P>
<P style="MARGIN: 0in 0in 0pt" class=MsoNormal>Paolo, can you work your
magic?<o:p></o:p></P>
<P style="MARGIN: 0in 0in 0pt" class=MsoNormal><o:p> </o:p></P>
<P style="MARGIN: 0in 0in 0pt" class=MsoNormal>Ciao,
-Paul<o:p></o:p></P></FONT></DIV></BODY></HTML>