<div class="gmail_quote"><div>Dear JISEOK KIM,</div><div><br></div><div>Did you check/visualize your geometry ?</div><div><br></div><div>The Box is too small and it is far from the Si-H system. </div><div><br></div><div><br>
</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
I'm having a difficulty on a geometry optimization using 'vc-relax'.<br>
I searched forum threads and followed various suggestions but the 'Total<br>
force' still does not converge..<br>
(but the pressures seems to be converged)<br>
<br>
The job steps I've taken as follows,<br>
<br>
1. optimized k-point and ecutwfc.<br>
2. optimized lattice parameter using Murnaghan fitting.<br>
3. 'relax' the geometry using the lattice constant obtained from step2,<br>
<br>
----------------------------------------------<br>
&control<br>
calculation = 'relax',<br>
restart_mode = 'from_scratch',<br>
prefix = '$NAME',<br>
pseudo_dir = '$PSEUDO_DIR/',<br>
outdir = '$OUT_DIR/',<br>
wf_collect = .TRUE.<br>
tstress = .TRUE.<br>
tprnfor = .TRUE.<br>
etot_conv_thr = 1.d-7<br>
forc_conv_thr = 1.d-6<br>
nstep = 1000<br>
/<br>
&system<br>
ibrav = 0,<br>
celldm(1) = 10.3345<br>
nat = 18,<br>
ntyp = 2,<br>
ecutwfc = 80.0,<br>
/<br>
&electrons<br>
diagonalization = 'cg',<br>
mixing_mode = 'plain',<br>
mixing_beta = 0.7,<br>
conv_thr = 1.0d-10,<br>
/<br>
&ions<br>
ion_dynamics = 'bfgs'<br>
bfgs_ndim = 3<br>
/<br>
ATOMIC_SPECIES<br>
Si 28.086 Si.pbe-rrkj.UPF<br>
H 1.0079 H.pbe-vbc.UPF<br>
CELL_PARAMETERS<br> ..........<br></blockquote><div> .......... </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
K_POINTS automatic<br>
1 1 16 0 0 0<br>
----------------------------------------------<br>
<br>
<br>
4. check if 'Total force' is converged -> OK.<br>
5. Take the final atomic coordinates from step4.<br>
6. Run 'vc-relax' as,<br>
<br>
----------------------------------------------<br>
&control<br>
calculation = 'vc-relax',<br>
restart_mode = 'from_scratch',<br>
prefix = '$NAME',<br>
pseudo_dir = '$PSEUDO_DIR/',<br>
outdir = '$OUT_DIR/',<br>
wf_collect = .TRUE.<br>
tstress = .TRUE.<br>
tprnfor = .TRUE.<br>
etot_conv_thr = 1.d-6<br>
forc_conv_thr = 1.d-6<br>
nstep = 10000<br>
/<br>
&system<br>
ibrav = 0,<br>
celldm(1) = 10.3345<br>
nat = 18,<br>
ntyp = 2,<br>
ecutwfc = 80.0,<br>
ecfixed = 70.0,<br>
qcutz = 150.0,<br>
q2sigma = 4.0,<br>
/<br>
&electrons<br>
diagonalization = 'cg',<br>
mixing_mode = 'plain',<br>
mixing_beta = 0.7,<br>
conv_thr = 1.0d-10,<br>
/<br>
&ions<br>
ion_dynamics = 'bfgs'<br>
bfgs_ndim = 3<br>
/<br>
&cell<br>
cell_dynamics = 'bfgs'<br>
press_conv_thr = 0.1d0<br>
press = 0.d0<br>
cell_factor = 2.d0<br>
/<br>
ATOMIC_SPECIES<br>
Si 28.086 Si.pbe-rrkj.UPF<br>
H 1.0079 H.pbe-vbc.UPF<br>---------<br></blockquote><div> ---------- </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
K_POINTS automatic<br>
1 1 16 0 0 0<br>
----------------------------------------------<br>
<br><br></blockquote></div><div><br></div>-- <br><b><font color="#000099"><span></span><span></span>With Best Regards:<br><br></font></b><div><b><font color="#000099">CH. Ramesh Kumar<br>Senior Research Fellow,<br>Computational Chemistry Lab,<br>
Indian Institute of Chemical Technology(IICT),</font></b></div><div><b><font color="#000099">Tarnaka, </font></b><b><font color="#000099"><div style="text-align:left;display:inline!important"><span style="color:rgb(0,0,0);font-weight:normal"><b><font color="#000099">Hyderabad.</font></b></span></div>
</font></b></div><br>