<div dir="ltr"><span style="font-size:12.8px;white-space:nowrap">Dear Sohail Ahmad</span><br><div><span style="font-size:12.8px;white-space:nowrap"><br></span></div><div><span style="font-size:12.8px;white-space:nowrap">using <b>nosym=.true</b>. in &system can solve the problem. But I dont know it is suitable or not. </span></div><div><span style="font-size:12.8px;white-space:nowrap"><br></span></div><div><span style="font-size:12.8px;white-space:nowrap">Regards</span></div><div><span style="font-size:12.8px;white-space:nowrap"><br></span></div><div><span style="font-size:12.8px;white-space:nowrap"><br></span></div></div><div class="gmail_extra"><br><div class="gmail_quote">2015-09-29 0:03 GMT+03:00 Sohail Ahmad <span dir="ltr"><<a href="mailto:sohailphysics@yahoo.co.in" target="_blank">sohailphysics@yahoo.co.in</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Dear QE users,<br>
I am using vc-relax first time to get the optimised structure of MoS2 monolayer.<br>
I believe the symmetry is breaking in the second step due to relaxation in x and y direction it is changing the number of k-points.<br>
<br>
What is the solution ??? (Somebody suggested a bigger cell with orthorhombic cell)<br>
But HOW and WHY ???<br>
<br>
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br>
     Error in routine checkallsym (2):<br>
     not orthogonal operation<br>
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br>
<br>
     stopping ...<br>
-----------------------------------------------------------------------------------------------------------------------<br>
input file as below<br>
<br>
&control<br>
  calculation = 'vc-relax',<br>
  restart_mode = 'from_scratch',<br>
  etot_conv_thr = 1.0d-5,<br>
  forc_conv_thr = 1.0d-4,<br>
  tstress = '.true.',<br>
  tprnfor = '.true.,<br>
  prefix = 'MoSml',<br>
  pseudo_dir = '/home/sohail/Espresso/espresso-5.0.1/pseudo',<br>
  outdir = './OUT',<br>
/<br>
&system<br>
  ibrav = 4, a = 3.16, b = 3.16, c = 15, cosac = 0.0, cosbc = 0.0, cosab = -0.5,<br>
  nat = 3, ntyp = 2,<br>
  ecutwfc = 70,<br>
  ecutrho = 300,<br>
  nbnd = 26,<br>
  occupations = 'smearing', smearing = 'gaussian', degauss = 0.001,<br>
  nspin = 2,<br>
  starting_magnetization(1) = 0.1d0,<br>
/<br>
&electrons<br>
  mixing_beta = 0.7d0,<br>
  conv_thr = 1.0d-15,<br>
  electron_maxstep = 500,<br>
/<br>
&ions<br>
 ion_dynamics = 'bfgs',<br>
/<br>
&cell<br>
 cell_dynamics = 'bfgs',<br>
 press = 0.d0,<br>
 press_conv_thr = 1.2d0,<br>
 cell_dofree = 'xy',<br>
 /<br>
ATOMIC_SPECIES<br>
Mo  95.96  Mo.pw91-n-van.UPF<br>
S   32.06  S.pw91-van_ak.UPF<br>
ATOMIC_POSITIONS {Angstrom}<br>
Mo  -0.000000016  1.824426860  3.072500000<br>
S    1.580000016  0.912213416  1.474800000<br>
S    1.580000016  0.912213416  4.670200000<br>
K_POINTS {AUTOMATIC}<br>
8 8 1 0 0 0<br>
<br>
<br>
Thanks<br>
Sohail Ahmad<br>
King Khalid University<br>
Abha, Saudi Arabia<br>
<br>
<br>
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</blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature"><div dir="ltr"><div><span style="font-size:12.8000001907349px"><br></span></div><div><span style="font-size:12.8000001907349px">Bahadır SALMANKURT</span></div><div><span style="font-size:12.8000001907349px">Sakarya University, TURKEY</span></div><span style="font-size:12.8000001907349px">Ph.D. student of Physics</span><br></div></div>
</div>