<div dir="ltr">Dear Manu,<div><br></div><div>Increasing ecut may be useful. Also <span style="font-family:arial,helvetica,sans-serif;font-size:12.8px">conv_thr is high, reduce it to </span><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px">1D-10 which is good for phonon calculation. For </span><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px">&inputph, add the following;</span></div><div><font face="arial, helvetica, sans-serif"><span style="font-size:12.8px"><br></span></font></div><div><font face="arial, helvetica, sans-serif"><span style="font-size:12.8px"><b>alpha_mix(1) = 0.3 </b></span></font></div><div><font face="arial, helvetica, sans-serif"><span style="font-size:12.8px"><br></span></font></div><div><font face="arial, helvetica, sans-serif"><span style="font-size:12.8px">I always use </span></font><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px">alpha_mix(1) as 0.3 or 0.5 when I have </span><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px">converge problem.</span><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px"> </span><font face="arial, helvetica, sans-serif"><span style="font-size:12.8px">Default value is 0.7. </span></font></div><div><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px"><br></span></div><div><span style="font-family:arial,helvetica,sans-serif;font-size:12.8px">Bests</span></div><div><font face="arial, helvetica, sans-serif"><span style="font-size:12.8px"><br></span></font></div><div><font face="arial, helvetica, sans-serif"><span style="font-size:12.8px"><br></span></font></div></div><div class="gmail_extra"><br><div class="gmail_quote">2016-06-08 23:23 GMT+03:00 Manu Hegde <span dir="ltr"><<a href="mailto:mhegde@uwaterloo.ca" target="_blank">mhegde@uwaterloo.ca</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Hello All,<br><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">I was trying to calculate phonon dispersion in PbTIO3, my SCF calculations went well, but I am struggling with ph.x. It is taking long time to converge. Any suggestions to  improve the input and make it faster?.<br><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"> Both SCF and Phonon input are below, please have a look. <br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br><br>&CONTROL<br>                 calculation = 'scf' ,<br>                restart_mode = 'from_scratch' ,<br>                      outdir = '/home/user/espresso-5.3.0/PBTIO/' ,<br>                  pseudo_dir = '/home/user/espresso-5.3.0/pseudo/' ,<br>                      prefix = 'perov',<br>                          tstress = .true.,<br>                         tprnfor = .true.,<br>                       verbosity = 'high',<br> /<br> &SYSTEM<br>                      <br>                           A = 3.97,<br>                       space_group = 221,<br>                         nat = 3,<br>                        ntyp = 3,<br>                     ecutwfc = 30.0 ,<br>                     <br> /<br> &ELECTRONS<br>                    conv_thr = 1D-6,<br>                   mixing_beta=0.3<br> /<br>ATOMIC_SPECIES<br>   Pb  207.20000  Pb.pz-d-van.UPF <br>   Ti   47.86700  Ti.pz-sp-van_ak.UPF <br>    O   15.99940  O.pz-van_ak.UPF <br>ATOMIC_POSITIONS crystal_sg <br>   Pb  1a    <br>   Ti  1b  0.5        <br>    O  0.5 0.5 0.0  <br>K_POINTS automatic <br>  8 8 8   0 0 0<br><br><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Phonon input <br><br><br>phonons of PbTio at grid<br>&inputph<br>        prefix = 'perov'<br>        <br>        ldisp = .true.,<br>        fildyn = 'pbtio.dyn',<br>        amass(1) = 207.2,<br>        amass(2) = 47.867,<br>        amass(3) = 15.9994<br>        outdir = '/home/user/espresso-5.3.0/PBTIO/'<br>        nq1 = 4,<br>        nq2 = 4,<br>        nq3 = 4,<br>        tr2_ph = 1.0d-12,<br>/<br><br><br><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Thanks and Regards,<br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Manu<br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">University of Waterloo<br></div></div>
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