<html><head><meta http-equiv="Content-Type" content="text/html; charset=gb2312"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Dear all,<div class=""><br class=""></div><div class="">I have been using Phonon package ( version 6.1) to compute electron-phonon coupling matrix elements. Following example 3 in Phonon package, I computed the elements of Al(bcc) and the elements are written in _ph0/al.phsave/elph.*.*.xml. According to phonon user¡¯s guide and developer¡¯s manual, the elements in these files are coupling matrix in the basis of normal mode, ie g_{q nu} and it has been scaled to phonon frequencies and masses. However, if I manually change masses in Phonon input file, the elements do not change. So, are you sure the elements are in normal mode basis and are scaled to masses? Also, what is the unit for the elements written in those files? I assume it is Rydberg?</div><div class=""><br class=""></div><div class="">Another question is about the elements at k=gamma and q=gamma. Because the el-ph coupling matrix elements are computed with < psi_mk+q | dvscf | psi_nk >. At k=gamma and q=gamma, I believe these quantities should be real numbers, right? However, I get complex numbers for Al at k=gamma, q=gamma. Here are first several elements:</div><div class=""><br class=""></div><div class=""><div class=""> <K_POINT.1></div><div class=""> <COORDINATES_XK type="real" size="3" columns="3"></div><div class=""> 0.000000000000000E+000 0.000000000000000E+000 0.000000000000000E+000</div><div class=""> </COORDINATES_XK></div><div class=""> <PARTIAL_ELPH type="complex" size="100"></div><div class=""> 1.173453794238444E-007, 5.551115123125783E-017</div><div class=""> -2.279566019787527E-002, <font color="#ff2600" class="">3.586239646544477E-001</font></div><div class=""> -4.862786020311256E-001,<font color="#ff2600" class=""> 2.450200129592524E-001</font></div><div class=""> 3.623894552425257E+000,<font color="#ff2600" class="">-5.173393946467373E-001</font></div><div class=""> -6.097101185043030E-009, 1.009496251869191E-008</div><div class=""> 2.988349845356453E-010, 9.034043582656359E-010</div><div class=""> 2.767334139619493E-010, 1.470082250376592E-010</div></div><div class=""><br class=""></div><div class="">Do I make any mistake in computing or interpreting the results? </div><div class=""><br class=""></div><div class="">Here¡¯s my input file for phonon calculation:</div><div class=""><div class=""> &inputph</div><div class=""> tr2_ph=1.0d-10,</div><div class=""> prefix='al',</div><div class=""> fildvscf='aldv',</div><div class=""> amass(1)=26.98,</div><div class=""> fildyn='./_ph0/al.dyn',</div><div class=""> outdir='./',</div><div class=""> electron_phonon='yambo',</div><div class=""> el_ph_sigma=0.005,</div><div class=""> el_ph_nsigma=10,</div><div class=""> asr = .true.</div><div class=""> zue = .false.</div><div class=""> epsil = .false.</div><div class=""> trans=.true.,</div><div class=""> ldisp=.true.</div><div class=""> nq1=5, nq2=5, nq3=5</div><div class=""> /</div></div><div class=""><br class=""></div><div class="">Thank you very much!</div><div class=""><br class=""></div><div class="">Han.</div><div class="">University of Chicago</div></body></html>