<div dir="ltr"><div><div><div><div><br></div>Dear Sridhar,<br><br></div>Thank you very much for your explanation regarding the error.<br><br></div>It helped me a lot.<br><br></div>Thank you.<br><div class="gmail_extra"><br>

<br><div class="gmail_quote">On Sun, Jun 1, 2014 at 9:48 AM, Sridhar Sadasivam <span dir="ltr"><<a href="mailto:sridhu88@gmail.com" target="_blank">sridhu88@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">

<div dir="ltr">If you want to compute electron-phonon interaction for a phonon of wavevector q, you will need electron wavefunctions at k and k+q. Thus your grid for scf should always be a multiple of your q-point grid for phonon calculations. Since 8 is a multiple of 2 and 4 but not 6, you are getting this error. Hope that helps.<div>



Sridhar</div><div>Purdue University</div></div><div class="gmail_extra"><br><br><div class="gmail_quote"><div><div class="h5">On Sun, Jun 1, 2014 at 9:36 AM, Peram sreenivasa reddy <span dir="ltr"><<a href="mailto:peramsreenivas@gmail.com" target="_blank">peramsreenivas@gmail.com</a>></span> wrote:<br>



</div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5"><div dir="ltr"><div><div>Dear Pwscf,<br><br><br></div>In my phonon calculations i got some error.<br>

<br></div><div>For nq1=2, nq2=2, nq3=2 and nq1=4, nq2=4, nq3=4 i did not get any errors.<br>

<br></div><div>But for nq1=6, nq2=6, nq3=6 grid i got the bellow error.<br>

</div><br><div><div>Diagonalizing the dynamical matrix<br><br>     q = (   -0.166666667   0.166666667  -0.166666667 ) <br><br> **************************************************************************<br>     omega( 1) =       1.218152 [THz] =      40.633179 [cm-1]<br>





     omega( 2) =       1.218152 [THz] =      40.633179 [cm-1]<br>     omega( 3) =       2.760322 [THz] =      92.074433 [cm-1]<br>     omega( 4) =       3.157206 [THz] =     105.313054 [cm-1]<br>     omega( 5) =       3.157206 [THz] =     105.313054 [cm-1]<br>





     omega( 6) =       3.160843 [THz] =     105.434373 [cm-1]<br>     omega( 7) =       6.119555 [THz] =     204.126381 [cm-1]<br>     omega( 8) =       6.129602 [THz] =     204.461528 [cm-1]<br>     omega( 9) =       6.129602 [THz] =     204.461528 [cm-1]<br>





     omega(10) =       9.495441 [THz] =     316.733825 [cm-1]<br>     omega(11) =       9.521102 [THz] =     317.589790 [cm-1]<br>     omega(12) =       9.521102 [THz] =     317.589790 [cm-1]<br> **************************************************************************<br>





<br>     Mode symmetry, C_3v (3m)   point group:<br><br>     omega(  1 -  2) =         40.6  [cm-1]   --> E    L_3           <br>     omega(  3 -  3) =         92.1  [cm-1]   --> A_1  L_1           <br>     omega(  4 -  5) =        105.3  [cm-1]   --> E    L_3           <br>





     omega(  6 -  6) =        105.4  [cm-1]   --> A_1  L_1           <br>     omega(  7 -  7) =        204.1  [cm-1]   --> A_1  L_1           <br>     omega(  8 -  9) =        204.5  [cm-1]   --> E    L_3           <br>





     omega( 10 - 10) =        316.7  [cm-1]   --> A_1  L_1           <br>     omega( 11 - 12) =        317.6  [cm-1]   --> E    L_3           <br><br> **************************************************************************<br>





     electron-phonon interaction  ...<br><br><br> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br>     from elphsum : error #         3<br>     q is not a vector in the dense grid<br> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br>





<br>     stopping ...<br><br> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br>     from elphsum : error #         3<br>     q is not a vector in the dense grid<br> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br>





<br clear="all"><div>This error came after completing my first q point. <br><br><br></div><div>Is this q grid is correct for the given k points mesh?<br><br></div><div>Is it better to increase it to  nq1=8, nq2=8, nq3=8. ?<br>





<br></div><div>Thank you very much in advance.<span><font color="#888888"><br><br><br><br><br></font></span></div><span><font color="#888888"><div><br><br><br>-- <br><i>P.V.SREENIVASA REDDY</i><br>

<i>Research Scholar<br>Department of Physics </i><br><br></div></font></span></div></div></div>
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