[Pw_forum] Problens with etot_vs_alat of gold

[Ari P Seitsonen]

Dear Aline A Bidoul,

   You might want to check how many atoms are in the fcc unit cell if you 
indeed use the FCC as the basis (ibrav = 2).

     Greetings,

        apsi

-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
   Ari Paavo Seitsonen / Ari.P.Seitsonen at iki.fi / http://www.iki.fi/~apsi/
   Institut für Chemie der Universität Zürich, CH-8057 Zürich
   Tel: +41 44 63 54 497  /  Mobile: +41 79 71 90 935


On Mon, 5 May 2014, Aline Bidoul wrote:

> Hi everyone!I'm new in Quantum-Espresso and i having problems to minimize que lattice parameter of gold
> The minimum energy is with 7.0A and in literature we find 4.07 A and in other programs i find 4.2
> I'm using this code to calculate the curve
> 
> #!/bin/sh
> ####################################################################
> #
> # define the following variables according to your needs
> #
> #espresso_dir=top_directory_of_espresso_package
> outdir=/home'
> pseudo_dir=/home/pseudo'
> ####################################################################
> 
> rm -f au.scf.out au.etot_vs_alat
> touch au.etot_vs_alat
> 
> for alat in  4.05 4.06 4.07 4.08 4.09 4.1 4.2 5.0 6.0 7.0 8.0 9.0 ; do
> 
> # self-consistent calculation
> cat > au.scf.in << EOF
> &control
>     calculation = 'scf'
>     prefix='gold',
>     pseudo_dir = pseudo_dir,
>     outdir= outdir,
>  /
>  &system
>     ibrav=  2, a=$alat , nat=  4, ntyp= 1,
>     ecutwfc = 40.0, ecutrho = 480.0,
>     occupations='smearing', smearing = 'mv', degauss = 0.002
>  /
>  &electrons
>     mixing_mode = 'local-TF'
>     mixing_beta = 0.7
>     conv_thr = 1.0d-6
>  /
> ATOMIC_SPECIES
>  Au  196.96654  Au.bp-van_ak.UPF
> ATOMIC_POSITIONS (crystal)
>  Au 0.00 0.00 0.00
>  Au 0.5  0.5  0.0
>  Au 0.5  0.0  0.5
>  Au 0.0  0.5  0.5
> K_POINTS automatic
>    8 8 8 1 1 1
> 
> EOF
> 
> pw.x < au.scf.in > au.scf.out
> 
> grep -e 'lattice parameter' -e ! au.scf.out | \
>       awk '/lattice/{a=$(NF-1)}/!/{print a, $(NF-1)}' >> au.etot_vs_alat
> 
> done
> 
> I find this in a tutorial of Professor Narasimhan. 7.0 A i think is large for gold, so i try to find for Silver and the alat was almost the same. I tested all the PP for gold that
> i find in the QE page, and has the same result with different energies values. If some one could help i will be grateful.
> 
> 
> --
> Aline A. BidoulEngenheira Física
> Mestranda em Engenharia Biomédica
> 
>