<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman,new york,times,serif;font-size:12pt">Dear Srijan,<br><br>Z* and \epsilon, therefore, LO-TO splitting are for semiconductors/insulators. <br>As you know, all valence bands are occupied, and conductivity bands are empty. Thus,<br>you can omit the smearing keyword to let pw.x know that you deal with a semiconductor.<br>Then you will got dyn1-file with Z* and \epsion, q2r.x and matdyn.x will take care about these <br>parameters and LO-TO splitting.<br><br>Having IFC (*.fc) file you can edit Z* and \epsilon.<br><br>See example06 and /Doc/PH.txt. <br><div> <br>Best regards,<br>Eyvaz.<br></div>P.S. So, they are not related with postprocessing<br>-------------------------------------------------------------------<br>Prof. Eyvaz Isaev, <br>Department of Physics, Chemistry, and Biology (IFM), Linkoping
University, Sweden <br>Theoretical Physics Department, Moscow State Institute of Steel & Alloys, Russia, <br>isaev@ifm.liu.se, eyvaz_isaev@yahoo.com<div><br></div><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><font face="Tahoma" size="2"><hr size="1"><b><span style="font-weight: bold;">From:</span></b> Srijan Kumar Saha <srijan.india@gmail.com><br><b><span style="font-weight: bold;">To:</span></b> PWSCF Forum <pw_forum@pwscf.org><br><b><span style="font-weight: bold;">Sent:</span></b> Mon, March 14, 2011 2:35:00 PM<br><b><span style="font-weight: bold;">Subject:</span></b> [Pw_forum] Phonon Dispersion with LO-TO splitting<br></font><br>
<br>Dear QE USERS,<br><br>The QE code takes note of the presence of Z* and epsilon in the
dynamical matrix file <br>and will add to the dynamical matrix the
non-analytic part corresponding to the <br>given <b>q</b>=>0. The 3-fold
degenerate optical modes are now split by the LO-TO splitting.<br><br>Here, I would like to know, whether during POST-PROCESSING, is it possible to manually add the <br>values of the Born-effective charge and dielectric constant (which has been taken from the Experiments <br>
and not the computed ones) in the
"dynamical matrix file" so that after POST-PROCESSING one can get <br>a phonon dispersion curve taking into account the experimental values of the Z* and Dielectric constant ? <br>If yes, then in which file and where, one should add the Z* and Dielectric constant manually ?<br>
<br>Looking forward to your kind reply.<br><br>Thanking you and with my best regards,<br><br>Srijan Kumar <br>R&D Assistant <br>JNCASR<br>Bangalore 560064 <br>
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