[Pw_forum] Re: choice of the pseudo, Ni(110)

[Varki Pagan (Peressi)]

On Tue, 22 Feb 2005, Varki Pagan (Peressi) wrote:



Thank you all, now it' s clear to me how to proceed.

you very kind,

thank you,

best regards,

varki.




>
> Hi all,
>
> i'm using pw in order to study a Ni(110) surface.
>
> I' m now just fixing the bulk properties, so i ran some loops to study the 
> variation of the minimum value of the energy and of the alat in the bulk.
>
> after doing that stuff, i tried using a different pseudo, obtaining quite 
> different results.
>
> i' m sorry for probably it' s a silly question, but how do i choose my pseudo 
> ?
>
> first used pseudo :
>
>         Perdew-Zunger (LDA) exch-corr
> 	 nonlinear core-correction
> 	 semicore state d in valence
> 	 Rabe Rappe Kaxiras Joannopoulos (ultrasoft)
>
> obtaining a0 = 6.47 alat and Emin =  -85.72192 Ry
>
>
> second used pseudo :
>
>         Perdew-Burke-Ernzerhof (PBE) exch-corr
> 	 nonlinear core-correction
> 	 semicore state d in valence
> 	 Rabe Rappe Kaxiras Joannopoulos (ultrasoft)
>
> obtaining a0 = 6.66 alat and Emin = -85.89509 Ry
>
>
> others parameters fixed in both the runs ( obtained as best choice for a 
> desired accuracy after different evaluation runs) :
>
> &control
>    calculation='scf'
>    restart_mode='from_scratch',
>    pseudo_dir = '/home/espresso/pseudo/',
>    outdir='/tmp/'
>    prefix='ni'
>    tprnfor = .true.,
>    tstress = .true.
> /
> &system
>    ibrav=2, celldm(1) =6.80, nat=1, ntyp=1,
>    nspin = 2,  starting_magnetization(1)=0.7,
>    ecutwfc = 24.0, ecutrho = 288.0,
>    occupations='smearing', smearing='methfessel-paxton', degauss=0.01
> /
> &electrons
>    diagonalization=''
>    conv_thr = 1.0e-8
>    mixing_beta = 0.7
> /
> ATOMIC_SPECIES
> Ni 58.69 NiUS.RRKJ3.UPF
>
> ATOMIC_POSITIONS
> Ni 0.0 0.0 0.0
> K_POINTS (automatic)
> 5 5 5 1 1 1
>
>
>
> So, i apologize once more 'cause probably it's a silly question, and thank 
> you all in advance for your attention.
>
> bye,
>
> varki pagan.
>
>
>