[QE-users] Getting convergence on a cell obtained from a cif using vc-relax
Arles V. Gil Rebaza
arvifis at gmail.com
Fri Jun 1 16:47:27 CEST 2018
Dear Reinaldo, are you sure that these values of ecutwfc = 40 and
ecutrho = 200 describe your system well? Probabily you should increase
these values, in order to describe the transition metal atom (Cu) and the
total energy (forces and pressure depends of the total energy). Try to
converge the total energy of the system respect to ecutwfc value performing
self-consistent calculation for different vaues of ecutwfc. Furthermore,
for US pseudopotential the ecutrho value is tipically 8 to 12 times ecutwfc
(see QE manual).
Best
Dr. Arles V. Gil Rebaza
Instituto de Física La Plata
La Plata - Argentina.
2018-06-01 11:20 GMT-03:00 Reinaldo Pis Diez <reinaldo.pisdiez at gmail.com>:
> 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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--
Arles V.
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