[Pw_forum] geometry optiiztion of metal clusters

[jia chen]

Dear Jennifer,

For that large supercell, I think gamma point is enough.

Bests
On Mon, Mar 28, 2011 at 4:19 PM, Wohlwend,	Jennifer L CTR USAF AFMC
AFRL/RXBT <Jennifer.Wohlwend.ctr at wpafb.af.mil> wrote:
> I’m trying to perform geometry optimization of some clusters and they are
> running extremely slow. For example a TiO2 anatase cluster of only 12 atoms
> has completed only a few self-consistent iterations after ~3 hours. I know I
> must be doing something wrong but I’ve not been able to spot it yet. For the
> TiO2 system, my input is as follows:
>
> &CONTROL
>
>                        title = Ti_relax ,
>
>                  calculation = 'relax' ,
>
>                 restart_mode = 'restart' ,
>
>                       outdir = './' ,
>
>                       wfcdir = './' ,
>
>                   pseudo_dir = '/hafs15/jen7182/espresso/pseudo/' ,
>
>                  lkpoint_dir = .true. ,
>
>                etot_conv_thr = 1.0D-6 ,
>
>                forc_conv_thr = 1.0D-6 ,
>
>                        nstep = 120 ,
>
>                      tstress = .true. ,
>
>                      tprnfor = .true. ,
>
>                       lberry = .false. ,
>
>  /
>
>  &SYSTEM
>
>                        ibrav = 1,
>
>                    celldm(1) = 50.0000000,
>
>                          nat = 12,
>
>                         ntyp = 2,
>
>                      ecutwfc = 55 ,
>
>                      ecutrho = 500 ,
>
>                  occupations = 'smearing' ,
>
>                      degauss = 0.02D0 ,
>
>                     smearing = 'methfessel-paxton' ,
>
>  /
>
>  &ELECTRONS
>
>                     conv_thr = 1.D-8 ,
>
> /
>
>  &IONS
>
>                 ion_dynamics = 'bfgs' ,
>
>   pot_extrapolation = "second_order",
>
>   wfc_extrapolation = "second_order",
>
>  /
>
> ATOMIC_SPECIES
>
>     Ti   47.87000  Ti.pw91-nsp-van.UPF
>
> 15.99960  O.pw91-van_ak.UPF
>
> ATOMIC_POSITIONS
>
> Ti      0.019646921155  -0.032104589149 0.072982942110
>
> Ti      -0.053021298671 0.015633269982  0.132549510485
>
> Ti      0.057125188587  0.058771047647  0.164020158511
>
> Ti      0.110388124153  0.105884441223  0.244068937730
>
> O       -0.023076017443 -0.044401500581 0.131365372724
>
> O       0.035579202732  -0.080351647885 0.029496520030
>
> O       -0.037172544158 0.018329722652  0.066778689936
>
> O       0.057973293750  0.014983392566  0.111654528302
>
> O       -0.014261394120 0.057693305910  0.168967680139
>
> O       0.116729745829  0.144794684381  0.294813978638
>
> O       0.083638150059  0.040575025164  0.225871612978
>
> O       0.091668444256  0.117426432280  0.178170567176
>
> K_POINTS automatic
>
> 4 4 4   1 1 1
>
> Any help would be greatly appreciated!!
>
> Thank you!
>
> Jennifer
>
> Jennifer L. Wohlwend, Ph.D.
>
> Thermal Sciences and Materials Branch
>
> Materials and Manufacturing Directorate
>
> Air Force Research Laboratory
>
> 2941 Hobson Way B654 R015
>
> Wright Patterson Air Force Base, OH 45433-7750
>
> Ctr: Universal Technology Corporation
>
> Phone: (937) 656-4918
>
> Email: jennifer.wohlwend.ctr at wpafb.af.mil
>
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>



-- 
Jia Chen