<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 14 (filtered medium)"><style><!--
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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>I’m sure several in the QE community have seen Helmut Eschrig’s recent paper in PRB followed by Emil Prodan’s Viewpoint commentary in Physics. Both can be found at <a href="http://physics.aps.org/viewpoint-for/10.1103/PhysRevB.82.205120">http://physics.aps.org/viewpoint-for/10.1103/PhysRevB.82.205120</a>. On the face of it, Eschrig’s conclusions appear to be good news for DFT based on plane-wave representations such as QE, but I’d like to hear other views as well. As I believe the electron-phonon interaction depends on the functional derivative of the charge density (or equivalent potential)(see the conclusions in the PRB paper), is it indeed good news for extending the QE package to include e-p extensions to cover LDA+U, a tool I’d dearly like to have?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I’m here at Fall MRS in Boston, and this morning there was an experimental talk concluding Si nanowires thinner than 5 nm were unstable (W2.5). Seems like a good QE exercise for some ambitious student out there.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Paul Grant<o:p></o:p></p><p class=MsoNormal>IBM Research Staff Member Emeritus<o:p></o:p></p></div></body></html>