<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>To the PWscf Community:<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Example07 is a tutorial on the use of pw.x and ph.x to calculate the Eliashberg parameters of a simple superconductor, in this case aluminum, whose transition temperature is approximately 1.2 K in bulk under ambient pressure and zero applied magnetic field.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Paragraph 1) of the README file contains the rather cryptic comment with respect to the use of a 16 x 16 x 16 MP grid in an scf calculation preparatory to calculating subsequent el-phon coefficients, “Note that the k-point grids used here are NOT dense enough for a serious calculation!!!”<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>In the context of Example07, then, what would, with respect to the size of MP grids, including nq-vectors, basis set size (ecutwfc), and respective convergence thresholds, constitute a “serious calculation?” Has such a calculation of the Eliashberg parameters of aluminum using QE been published (I am aware of Wierzboska’s paper on Nb)?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks, -Paul<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>W2AGZ Technologies<o:p></o:p></p><p class=MsoNormal>Staff Associate, JPL-NASA<o:p></o:p></p><p class=MsoNormal><a href="http://www.w2agz.com">www.w2agz.com</a><o:p></o:p></p><p class=MsoNormal><a href="mailto:w2agz@w2agz.com">w2agz@w2agz.com</a><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>