[QE-users] Getting convergence on a cell obtained from a cif using vc-relax
Reinaldo Pis Diez
reinaldo.pisdiez at gmail.com
Sat Jun 2 16:04:34 CEST 2018
Dear Arles,
Thanks for your answer. I'm using the GBRV pseudopotentials family,
in which the authors indicate that "In particular, the GBRV
potentials are designed to run at a plane-wave cutoff of 40 Ry and a
charge-density cutoff of 200 Ry..." [Comp Mat Sci 81 (2104) 446). I
agree that the systems tested by the authors do not include TM
complexes, so, probably, I cannot expect a good transferability for
PS, so this could be the error's source. I'll investigate this issue.
Regards,
Reinaldo
On 01/06/18 11:47, Arles V. Gil Rebaza wrote:
> 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 <mailto: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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