<div dir="ltr"><div>Hello,</div><div><br></div>A few issues I could spot by looking at the input. Should use only 1 k point along the direction of the vacuum. Also, it will be more reasonable if the number of k points in the direction of celldm(2) is about twice of that in the direction of celldm(1). The ecutwfc is too large, 60-80 Ry should be fine.<div><br></div><div>Best wishes,</div><div>Biswajit </div></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div>Biswajit Santra</div><div>Mobile: +1-609-227-9202</div><div><a href="http://www.princeton.edu/~bsantra/" style="font-size:12.8px" target="_blank">http://www.princeton.edu/~bsantra/</a><br></div></div></div></div></div>
<br><div class="gmail_quote">On Mon, Feb 20, 2017 at 12:13 PM, Namita Narendra <span dir="ltr"><<a href="mailto:nnarend@ncsu.edu" target="_blank">nnarend@ncsu.edu</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">Hi,<div><br></div><div>I am trying to relax a (111) diamond/cubic-BN slab and the total force on the atom is not converging. Initially, the scf cycle itself was not converging and I needed to introduce smearing with degauss=0.01 to achieve scf convergence. Now, the relaxation is not converging and the total force on the atom is oscillating. I have tried mixing of 'local-TF', reduced mixing_beta, used damped ion dynamics and tried LDA pseudopotential. None of this has helped with the convergence issue. Attached below is the input file used.</div><div><br></div><div><div> &CONTROL</div><div><span class="m_3383467429906226334gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>calculation = 'relax' ,</div><div><span class="m_3383467429906226334gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>restart_mode = 'from_scratch' ,</div><div><span class="m_3383467429906226334gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>wf_collect = .true. ,</div><div><span class="m_3383467429906226334gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>outdir = '/share2/nnarend/espresso/c_<wbr>bn1' ,</div><div><span class="m_3383467429906226334gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>pseudo_dir = '/home/nnarend/pseudo' ,</div><div><span class="m_3383467429906226334gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>prefix = 'C_BN_1' ,</div><div><span class="m_3383467429906226334gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>tstress = .true. ,</div><div><span class="m_3383467429906226334gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>tprnfor = .true. ,</div><div> forc_conv_thr=1.0D-3,</div><div> etot_conv_thr=1.0D-4</div><div> /</div><div> &SYSTEM</div><div><span class="m_3383467429906226334gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>ibrav = 8,</div><div><span class="m_3383467429906226334gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>celldm(1) = 8.291523, </div><div> celldm(2)=0.57735,</div><div> celldm(3)=6,</div><div> nat = 24,</div><div><span class="m_3383467429906226334gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>ntyp = 3,</div><div><span class="m_3383467429906226334gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>ecutwfc=180.0,</div><div> occupations='smearing',</div><div> smearing='cold',</div><div> degauss=0.01</div><div><br></div><div> /</div><div> &ELECTRONS</div><div><span class="m_3383467429906226334gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>conv_thr = 1.0d-8,</div><div><span class="m_3383467429906226334gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>mixing_mode = 'plain' ,</div><div><span class="m_3383467429906226334gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>mixing_beta = 0.3 ,</div><div><span class="m_3383467429906226334gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>diagonalization = 'david' ,</div><div> /</div><div> &IONS</div><div> /</div><div>ATOMIC_SPECIES</div><div> B 10.811 B.pbe-nc.UPF </div><div> N 14.007 N.pbe-nc.UPF </div><div> C 12.011 C.pbe-nc.UPF </div><div><br></div><div>ATOMIC_POSITIONS alat</div><div>C 0.000000 0.000000 0.000000</div><div>C 0.500000 0.288675 0.000000</div><div>C 0.166667 0.288675 0.117851</div><div>C 0.666667 0.000000 0.117851</div><div>C 0.166667 0.288675 0.471404</div><div>C 0.666667 0.000000 0.471404</div><div>C 0.333333 0.000000 0.589255</div><div>C 0.833333 0.288675 0.589255</div><div>C 0.333333 0.000000 0.942808</div><div>C 0.833333 0.288675 0.942808</div><div>C 0.000000 0.000000 1.060659</div><div>C 0.500000 0.288675 1.060659</div><div>B 0.000000 0.000000 1.414212</div><div>B 0.500000 0.288675 1.414212</div><div>N 0.166667 0.288675 1.532063</div><div>N 0.666667 0.000000 1.532063</div><div>B 0.166667 0.288675 1.885616</div><div>B 0.666667 0.000000 1.885616</div><div>N 0.333333 0.000000 2.003467</div><div>N 0.833333 0.288675 2.003467</div><div>B 0.333333 0.000000 2.357020</div><div>B 0.833333 0.288675 2.357020</div><div>N 0.000000 0.000000 2.474871</div><div>N 0.500000 0.288675 2.474871</div><div><br></div><div>K_POINTS automatic</div><div>8 8 6 0 0 0</div><div><br></div><div>Below is the force at the end of each bfgs cycle</div><div> </div></div><div><div> Total force = 0.492043 Total SCF correction = 0.000193</div><div> Total force = 0.170844 Total SCF correction = 0.000253</div><div> Total force = 0.049967 Total SCF correction = 0.000085</div><div> Total force = 0.038773 Total SCF correction = 0.000075</div><div> Total force = 0.042155 Total SCF correction = 0.000056</div><div> Total force = 0.046807 Total SCF correction = 0.000072</div><div> Total force = 0.044401 Total SCF correction = 0.000064</div><div> Total force = 0.034652 Total SCF correction = 0.000095</div><div> Total force = 0.033861 Total SCF correction = 0.000065</div><div> Total force = 0.107334 Total SCF correction = 0.000129</div><div> Total force = 0.071144 Total SCF correction = 0.000057</div><div> Total force = 0.053109 Total SCF correction = 0.000077</div><div> Total force = 0.058897 Total SCF correction = 0.000087</div><div> Total force = 0.075144 Total SCF correction = 0.000061</div><div> Total force = 0.109071 Total SCF correction = 0.000025</div><div> Total force = 0.121561 Total SCF correction = 0.000042</div><div> Total force = 0.128205 Total SCF correction = 0.000048</div><div> Total force = 0.138713 Total SCF correction = 0.000070</div></div><div><br></div><div>Thanks,</div><div>Namita</div></div>
<br>______________________________<wbr>_________________<br>
Pw_forum mailing list<br>
<a href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br>
<a href="http://pwscf.org/mailman/listinfo/pw_forum" rel="noreferrer" target="_blank">http://pwscf.org/mailman/<wbr>listinfo/pw_forum</a><br></blockquote></div><br></div>