[Pw_forum] NEB calculation

Layla Martin-Samos lmartinsamos at gmail.com
Mon Apr 18 13:13:46 CEST 2011


Dear Savita, atention the NEB input has changed in version 4.3. There is an
independent executable that parses a file, see example17. For identifying
the last image configuration, maybe you should make a simple relaxation of
CO at a fcc site and O very close to CO. Then you can start a NEB
calculation with  first image as CO and O at two near fcc sites and the last
image as the relaxed configuration obtained from the previous relaxation.

cheers

Layla

2011/4/18 <psavita at crlindia.com>

> Dear Layla and Prasenjeet,
>
> I think I should take Layla's suggestion and first consider CO2 formation.
> But then can I assume that O moves towards CO and CO2 forms at atop?
> Also as per Prasenjeet's advice, I should reduce vacuum layer to 25 bohr.
> I am giving here my input file for you to comment more.
> Thank you so much.
>
>
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> &CONTROL
>   calculation = 'neb',
>   restart_mode = 'from_scratch'
>   prefix='pt_co',
>   pseudo_dir  =
> "/home/nano/sivaram/simulation_zone/dft_simulation/year_2011_work/NEB",
>   outdir      =
> "/home/nano/sivaram/simulation_zone/dft_simulation/year_2011_work/NEB/relax",
> !  nstep       = 50,
> /
> &SYSTEM
>   ibrav       = 0,
>   nat         = 15,
>   ntyp        = 3,
>   ecutwfc     = 60.00,
>   ecutrho     = 360.00,
>   occupations = "smearing",
>   smearing    = "mp",
>   degauss     = 0.014699,
>   nspin       = 2,
>   starting_magnetization = 0.5
> /
> &ELECTRONS
>   electron_maxstep = 100,
>   conv_thr    = 1.D-7,
>   mixing_beta = 0.2,
>   diagonalization = 'cg'
> /
> &IONS
>   ds                = 2.0d0,
>   opt_scheme        = "broyden",
>   num_of_images     = 5,
>   k_max             = 0.4,
>   k_min             = 0.3,
>   CI_scheme         = "no-CI"
>   pot_extrapolation = "second_order",
>   wfc_extrapolation = "second_order",
>   path_thr          = 0.1d0
> /
> CELL_PARAMETERS
> 10.476 0 0
> 0  9.0727 0
> 0 0 40.215
> ATOMIC_SPECIES
> Pt  195.08  Pt.pw91-n-van.UPF
> O   15.999  O.pw91-van_ak.UPF
> C   12.011  C.pw91-van_ak.UPF
> ATOMIC_POSITIONS {bohr}
> first_image
> Pt       0.000000000   0.000000000   0.000000000
> Pt       5.238100000   0.000000000   0.000000000
> Pt       2.619050000   4.536328000   0.000000000
> Pt       7.857150000   4.536328000   0.000000000
> Pt       2.619088571   1.512240622   4.513968243
> Pt       7.857077843   1.512255365   4.514105935
> Pt       5.238032011   6.048542598   4.513881620
> Pt      10.476075613   6.048536230   4.513989805
> Pt       0.000134895   3.029013846   9.028523678
> Pt       5.238095443   3.029034864   9.028457281
> Pt       2.619088295   7.565397431   9.028126889
> Pt       7.857080929   7.565358308   9.028145500
> C       7.857080929   7.565358308    11.5281455
> O       7.857080929   7.565358308    13.7013455
> O       2.619050000   4.536328000    11.5281455
> last_image
> Pt       0.000000000   0.000000000   0.000000000
> Pt       5.238100000   0.000000000   0.000000000
> Pt       2.619050000   4.536328000   0.000000000
> Pt       7.857150000   4.536328000   0.000000000
> Pt       2.619088571   1.512240622   4.513968243
> Pt       7.857077843   1.512255365   4.514105935
> Pt       5.238032011   6.048542598   4.513881620
> Pt      10.476075613   6.048536230   4.513989805
> Pt       0.000134895   3.029013846   9.028523678
> Pt       5.238095443   3.029034864   9.028457281
> Pt       2.619088295   7.565397431   9.028126889
> Pt       7.857080929   7.565358308   9.028145500
> C        3.9286        5.2972       20.000
> O        3.9286        3.1240       20.0
> O        3.9286        7.4704       20.0
> K_POINTS {automatic}
>  6 6 3 0 0 0
>
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> Savita Pundlik
> Computational Materials Applied Research Group
> Computational Research Laboratories Ltd.,
> Taco House, Damle Path, Off Law College Road
> Pune - 411004, India.
>
>
>
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