Dear folks,
I usually help some experimentalist fellows from the Center I belong
by calculating geometries, cell parameters, vibrational frequencies,
electronic transitions, etc, of transition metal complexes. As the
cif file is often available, I use it to create the input file for
PWScf using Virtual Nano Lab from Quantum Wise.
Although convergence of the vc-relax job is usually achieved, some
cases are more problematic. Job ends with a high pressure and with
atomic forces far from thresholds when 'bfgs' is used both for &ions
and &cell namelists. Using 'damp' does not help to get geometry and
cell parameters optimized. Thus my (very general) question is: does
anybody know an strategy to systematically get convergence when
doing vc-relax? A link to a tutorial or a document is welcome.
For completeness, the input of one of the problematic cases is
appended below. By the way, I'm using "Program PWSCF v.6.1 (gpu tag
v1.0)" compiled with PGI compilers and MKL libraries on a CentOS box
with a Titan X (Pascal) gpu.
Thanks in advance
Reinaldo
Center of Inorganic Chemistry
Natl Univ of La Plata, Argentina
Input follows....
&CONTROL
title = 'Cu-ovatpnh2'
calculation = 'vc-relax'
restart_mode = 'from_scratch'
outdir = './'
pseudo_dir = './'
prefix = 'Cu-ovatpnh2'
etot_conv_thr = 0.0001
forc_conv_thr = 0.0004
tstress = .true.
tprnfor = .true.
nstep = 200
/
&SYSTEM
ibrav = 14
celldm(1) = 9.9320792573d0
celldm(2) = 2.0161515879d0
celldm(3) = 2.1156030541d0
celldm(4) = -0.1705259449d0
celldm(5) = -0.0219091103d0
celldm(6) = -0.2238523262d0
nat = 59
ntyp = 6
ecutwfc = 40
ecutrho = 200
input_dft = 'pbe'
occupations = 'smearing'
smearing = 'mv'
degauss = 0.005
nspin = 2
starting_magnetization(1) = 0.7
/
&ELECTRONS
conv_thr = 1d-06
mixing_beta = 0.6
mixing_mode = 'plain'
mixing_ndim = 8
diagonalization = 'david'
/
&IONS
ion_dynamics = 'bfgs'
/
&CELL
cell_dynamics = 'bfgs'
press = 0.5
/
ATOMIC_SPECIES
Cu 63.546000d0 cu_pbe_v1.2.uspp.F.UPF
C 12.010700d0 c_pbe_v1.2.uspp.F.UPF
H 1.007940d0 h_pbe_v1.4.uspp.F.UPF
N 14.006700d0 n_pbe_v1.2.uspp.F.UPF
O 15.999400d0 o_pbe_v1.2.uspp.F.UPF
S 32.065000d0 s_pbe_v1.4.uspp.F.UPF
ATOMIC_POSITIONS (crystal)
C 0.082231085 0.204570350 0.616545553
C 0.917768915 0.795429650 0.383454447
C 0.172973917 0.203448044 0.733466608
C 0.827026083 0.796551956 0.266533392
H 0.367673209 0.258122966 0.770942028
H 0.632326791 0.741877034 0.229057972
C 0.987334077 0.125087827 0.797766960
C 0.012665923 0.874912173 0.202233040
H 1.019591574 0.112838755 0.892010655
H -0.019591574 0.887161245 0.107989345
C 0.756454381 0.067986708 0.729401520
C 0.243545619 0.932013292 0.270598480
H 0.580696185 0.004985342 0.755622580
H 0.419303815 0.995014658 0.244377420
C 0.224564542 0.266351629 0.518206870
C 0.775435458 0.733648371 0.481793130
H 0.388829444 0.346391746 0.560989945
H 0.611170556 0.653608254 0.439010055
H 0.304022379 0.192372172 0.457292153
H 0.695977621 0.807627828 0.542707847
C 0.956901991 0.245893003 0.340167231
C 0.043098009 0.754106997 0.659832769
H 0.022416710 0.153595990 0.313033710
H 0.977583290 0.846404010 0.686966290
C 0.771131988 0.269306261 0.255617666
C 0.228868012 0.730693739 0.744382334
C 0.652850645 0.378765293 0.282708985
C 0.347149355 0.621234707 0.717291015
C 0.462994923 0.392175655 0.192940332
C 0.537005077 0.607824345 0.807059668
C 0.403148927 0.302768506 0.084001267
C 0.596851073 0.697231494 0.915998733
H 0.259814627 0.314740185 0.016757517
H 0.740185373 0.685259815 0.983242483
C 0.525750373 0.196269824 0.058490144
C 0.474249627 0.803730176 0.941509856
H 0.478830729 0.128376775 0.971151210
H 0.521169271 0.871623225 0.028848790
C 0.705969389 0.179966480 0.142934709
C 0.294030611 0.820033520 0.857065291
H 0.804698818 0.098652977 0.124221693
H 0.195301182 0.901347023 0.875778307
C 0.184454672 0.523754793 0.135830920
C 0.815545328 0.476245207 0.864169080
H 0.287576875 0.544363666 0.053314825
H 0.712423125 0.455636334 0.946685175
H 0.118308380 0.611071476 0.178999457
H 0.881691620 0.388928524 0.821000543
H 0.013394359 0.440437861 0.110093147
H 0.986605641 0.559562139 0.889906853
N 0.053284394 0.319764373 0.444382321
N 0.946715606 0.680235627 0.555617679
O 0.705759527 0.466685324 0.381694456
O 0.294240473 0.533314676 0.618305544
O 0.356827705 0.498376849 0.225196110
O 0.643172295 0.501623151 0.774803890
S 0.766003561 0.110202377 0.587178900
S 0.233996439 0.889797623 0.412821100
Cu -0.000000000 0.500000000 0.500000000
K_POINTS {automatic}
3 3 3 0 0 0
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