<span style="font-family:tahoma,sans-serif">Dear QE users,</span><br style="font-family:tahoma,sans-serif"><span style="font-family:tahoma,sans-serif">am trying to relax 3 layer SnO2 (110) surface
supercell of 52 atoms but the calculation
does not converge .i've tried this for the last 3 weeks but
unsuccesful. varied several parameters in the input file but the problem
persists.</span><br style="font-family:tahoma,sans-serif"><span style="font-family:tahoma,sans-serif">i experienced an error </span><br style="font-family:tahoma,sans-serif"><span style="color:rgb(0,0,127);font-family:tahoma,sans-serif">from checkallsym : error # 1</span><br style="color:rgb(0,0,127);font-family:tahoma,sans-serif">
<span style="color:rgb(0,0,127);font-family:tahoma,sans-serif"> some of the original symmetry operations not satisfied </span><br style="font-family:tahoma,sans-serif"><span style="font-family:tahoma,sans-serif">
but included nosym=.true. the problem didn't recur but still no convergence</span><br style="font-family:tahoma,sans-serif"><span style="font-family:tahoma,sans-serif">The bottom atoms are fixed.</span><br style="font-family:tahoma,sans-serif">
<span style="font-family:tahoma,sans-serif">my kpoints and ecut are reduced to ensure fast convergence, once the problem is fixed i will adjust them.</span><br style="font-family:tahoma,sans-serif"><span style="font-family:tahoma,sans-serif">
here is the input file</span><br style="font-family:tahoma,sans-serif"><span style="font-family:tahoma,sans-serif">please welcome any assistance on this.</span><br>&CONTROL <br>
restart_mode='from_scratch', <br> calculation='relax', <br>
outdir='./',<br> pseudo_dir='/home/mikeat/Applications/espresso-4.3.2/pseudo/',<br> prefix = 'SnOru_exc1',<br> tstress = .t.,<br> tprnfor = .t.,<br> etot_conv_thr = 1.d-5,<br>
forc_conv_thr = 1.d-4 <br> verbosity = 'high'<br><br>/<br>&SYSTEM<br> ibrav=6, celldm(1)=44.7607,<br> celldm(3)=0.5084,<br> nat= 52, ntyp= 2,<br> ecutwfc =10,ecutrho = 120,<br>
occupations='smearing', smearing='marzari-vanderbilt', degauss=0.07<br> nosym = .true.<br>/<br>&ELECTRONS<br> diagonalization = 'david'<br> mixing_mode = 'local-TF',<br>
mixing_beta = 0.3,<br> conv_thr = 1.0e-8,<br>/<br>&IONS<br><br>/<br>ATOMIC_SPECIES<br> Sn 50.011 Sn.pw91-n-van.UPF <br>
O 15.9994 O.pw91-<br>van_ak.UPF <br>
ATOMIC_POSITIONS {bohr} <br>Sn 8.952203138 26.85642044 -0.000000000<br>Sn 8.952203138 26.85642044 6.021425723<br>
Sn 17.90421730 26.85642044 -0.000000000<br>Sn 17.90421730 26.85642044 6.021425723<br>Sn 13.42821022 22.38041336 3.010712862<br>Sn 13.42821022 22.38041336 9.032138585<br>Sn 8.952203138 35.80862358 -0.000000000<br>
Sn 8.952203138 35.80862358 6.021425723<br>Sn 17.90421730 35.80862358 -0.000000000 0 0 0<br>Sn 17.90421730 35.80862358 6.021425723 0 0 0<br>Sn 4.476007083 31.33242752 3.010712862<br>
Sn 4.476007083 31.33242752 9.032138585<br>Sn 13.42821022 31.33242752 3.010712862<br>Sn 13.42821022 31.33242752 9.032138585<br>Sn 22.38041336 31.33242752 3.010712862 0 0 0<br>
Sn 22.38041336 31.33242752 9.032138585 0 0 0<br>Sn 13.42821022 40.28463066 3.010712862 0 0 0<br>Sn 13.42821022 40.28463066 9.032138585 0 0 0<br>O 11.70043294 29.60483921 -0.000000000<br>
O 11.70043294 29.60483921 6.021425723<br>O 20.65263607 29.60483921 -0.000000000 0 0 0<br>O 15.155987510 24.10819064 -0.000000000 0 0 0<br>O 20.65263607 29.60483921 6.021425723 0 0 0<br>
O 15.155987510 24.10819064 6.021425723 0 0 0<br>O 10.67998042 25.12864316 3.010712862<br>O 7.224425854 28.58419773 3.010712862<br>O 7.224425854 28.58419773 9.032138585<br>
O 10.67998042 25.12864316 9.032138585<br>O 16.17644002 28.58419773 3.010712862<br>O 16.17644002 28.58419773 9.032138585<br>O 11.70043294 38.55685338 -0.000000000<br>O 6.203784367 33.06020481 -0.000000000<br>
O 11.70043294 38.55685338 6.021425723<br>O 6.203784367 33.06020481 6.021425723<br>O 15.155987510 33.06020481 -0.000000000<br>O 15.155987510 33.06020481 6.021425723<br>O 10.679980420 34.0808463 3.010712862<br>
O 10.679980420 34.0808463 9.032138585<br>O 19.631994590 34.0808463 3.010712862<br>O 19.631994590 34.0808463 9.032138585<br>O 16.176440020 37.53640086 3.010712862<br>
O 16.176440020 37.53640086 9.032138585<br>Sn 8.952203138 26.85642044 12.04285145<br>Sn 17.90421730 26.85642044 12.04285145<br>Sn 8.952203138 35.80862358 12.04285145<br>Sn 17.90421730 35.80862358 12.04285145 0 0 0<br>
O 11.70043294 29.60483921 12.04285145<br>O 20.65263607 29.60483921 12.04285145 0 0 0<br>O 15.15598751 24.10819064 12.04285145 0 0 0<br>O 11.70043294 38.55685338 12.04285145<br>
O 6.203784367 33.06020481 12.04285145<br>O 15.15598751 33.06020481 12.04285145<br> <br>K_POINTS {automatic}<br><br> 2 2 3 0 0 0<br><br> <br>VICTOR KIRUI MENG'WA,MSC STUDENT<br>CHEPKOILEL UNIVERSITY COLLEGE,<br>
COMPUTATIONAL PHYSICS GROUP,<br>ELDORET, KENYA<br><br>