<div dir="ltr"><div><div>The last part of this message: <a href="https://www.mail-archive.com/pw_forum@pwscf.org/msg33028.html">https://www.mail-archive.com/pw_forum@pwscf.org/msg33028.html</a><br></div>may be of interest for you. I also remember hard-to-converge phonons with some pseudopotentials, both ultrasoft (notably old Vanderbilt USPP) and norm-conserving (N and O may be very hard)<br><br></div>Paolo<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Nov 16, 2017 at 10:09 AM, Francesco Moriggi <span dir="ltr"><<a href="mailto:frank7793@live.it" target="_blank">frank7793@live.it</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<p>Hello, i'm Francesco Moriggi, a master student at the Milan University, i have a problem with ph.x. I am calculating NO frequency and i'm not reaching a convergence in values compared to cutoff energy, using norm conserving and ultrasoft pseudopotentials.
Values i get are (i've put an image too in the email): </p>
<div class="m_-5943775721304937551moz-forward-container">
<p><b>Cutoff freq Norm freq US</b></p>
<b></b>
<p><b>75 1879.0 1844.4</b></p>
<b></b>
<p><b>80 1875.5 1858.2</b></p>
<b></b>
<p><b>85 1890.6 1907.1</b></p>
<b></b>
<p><b>90 1923.5 1895.2</b></p>
<b></b>
<p><b>100 1889.6 1909.3</b></p>
<b></b>
<p><b>110 1914.2 1893.1</b></p>
<b></b>
<p><b>120 1890.5 1900.4</b></p>
<b></b>
<p><b>130 1890.7 1901.0</b></p>
<b></b>
<p><b>140 1914.7 1890.9</b></p>
<b></b>
<p><b>150 1886.9 ////</b></p>
<p>With Gaussian (aug-cc-pv5Z) i've got <b>1889.21</b> cm-1.<br>
</p>
<p>An example of the input of geometry optimization is:</p>
<p><b>&CONTROL</b><b><br>
</b><b> calculation = "relax",</b><b><br>
</b><b> prefix = "NO",</b><b><br>
</b><b> pseudo_dir = "/galileo/home/userexternal/<wbr>fmoriggi/QE/NO/pseudoNO/<wbr>ultrasoft",</b><b><br>
</b><b> outdir = "./out",</b><b><br>
</b><b>/</b><b><br>
</b><b>&SYSTEM</b><b><br>
</b><b> ibrav = 1,</b><b><br>
</b><b> a = 20,</b><b><br>
</b><b> nat = 2,</b><b><br>
</b><b> ntyp = 2,</b><b><br>
</b><b> nspin = 2,</b><b><br>
</b><b> ecutwfc = 150.D0,</b><b><br>
</b><b> ecutrho = 1200.D0,</b><b><br>
</b><b> occupations = 'smearing', smearing = 'gauss', degauss=0.02,</b><b><br>
</b><b> starting_magnetization(1)=-0.<wbr>9,</b><b><br>
</b><b> starting_magnetization(2)=1.5,</b><b><br>
</b><b>/</b><b><br>
</b><b>&ELECTRONS</b><b><br>
</b><b> electron_maxstep = 500,</b><b><br>
</b><b> conv_thr = 1.D-7,</b><b><br>
</b><b> mixing_beta = 0.7D0,</b><b><br>
</b><b>/</b><b><br>
</b><b>&IONS</b><b><br>
</b><b>/</b><b><br>
</b><b>ATOMIC_SPECIES</b><b><br>
</b><b>O 16.00 O.pbe-van_ak.UPF</b><b><br>
</b><b>N 14.00 N.pbe-van_ak.UPF</b><b><br>
</b><b>ATOMIC_POSITIONS {angstrom}</b><b><br>
</b><b>N 1.16 0.0 0.0</b><b><br>
</b><b>O 0.000 0.0 0.0 0 0 0</b><b><br>
</b><b>K_POINTS</b><b><br>
</b><b>1</b><b><br>
</b><b>0.0 0.0 0.0 1.0</b></p>
<p>Later i've done an scf with a better conv_thr. This is the input.<br>
</p>
<p><b>&CONTROL</b><b><br>
</b><b> calculation = "scf",</b><b><br>
</b><b> prefix = "150",</b><b><br>
</b><b> pseudo_dir = "/galileo/home/userexternal/<wbr>fmoriggi/QE/NO/pseudoNO/<wbr>ultrasoft",</b><b><br>
</b><b> outdir = "./out150",</b><b><br>
</b><b>/</b><b><br>
</b><b>&SYSTEM</b><b><br>
</b><b> ibrav = 1,</b><b><br>
</b><b> a = 20,</b><b><br>
</b><b> nat = 2,</b><b><br>
</b><b> ntyp = 2,</b><b><br>
</b><b> nspin = 2,</b><b><br>
</b><b> ecutwfc = 150.D0,</b><b><br>
</b><b> ecutrho = 1200.D0,</b><b><br>
</b><b> occupations = 'smearing', smearing = 'gauss', degauss=0.02,</b><b><br>
</b><b> starting_magnetization(1)=-0.<wbr>9,</b><b><br>
</b><b> starting_magnetization(2)=1.5,</b><b><br>
</b><b>/</b><b><br>
</b><b>&ELECTRONS</b><b><br>
</b><b> electron_maxstep = 500,</b><b><br>
</b><b> conv_thr = 1.D-9,</b><b><br>
</b><b> mixing_beta = 0.7D0,</b><b><br>
</b><b>/</b><b><br>
</b><b>&IONS</b><b><br>
</b><b>/</b><b><br>
</b><b>ATOMIC_SPECIES</b><b><br>
</b><b>O 16.00 O.pbe-van_ak.UPF</b><b><br>
</b><b>N 14.00 N.pbe-van_ak.UPF</b><b><br>
</b><b>ATOMIC_POSITIONS {angstrom}</b><b><br>
</b><b>N 1.166278 0.0 0.0</b><b><br>
</b><b>O 0.000 0.0 0.0 0 0 0</b><b><br>
</b><b>K_POINTS</b><b><br>
</b><b>1</b><b><br>
</b><b>0.0 0.0 0.0 1.0</b></p>
<p>And then i run the ph.x with this input:</p>
<p><b>phonon calculation - NO</b><b><br>
</b><b> &inputph</b><b><br>
</b><b> tr2_ph=4.0d-12,</b><b><br>
</b><b> prefix='150'</b><b><br>
</b><b> amass(1)=14.007,</b><b><br>
</b><b> amass(2)=15.9994,</b><b><br>
</b><b> outdir='/galileo/home/<wbr>userexternal/fmoriggi/QE/NO/<wbr>relax/ultra/out150'</b><b><br>
</b><b> /</b><b><br>
</b><b> 0.0 0.0 0.0</b></p>
<p>If you can help me it would be very useful to my future TiO2 based calculations.<br>
<br>
<br>
Best regards,</p>
<p>Francesco Moriggi<br>
</p>
<p>Webpage: <a class="m_-5943775721304937551moz-txt-link-freetext" href="http://users.unimi.it/ceotto/about_FrancescoMoriggi.html" target="_blank">
http://users.unimi.it/ceotto/<wbr>about_FrancescoMoriggi.html</a><br>
</p>
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