[Pw_forum] Problens with etot_vs_alat of gold

[Arles V. Gil Rebaza]

Dear Aline, if you are using FCC structure (ibrav=2), you must to use only
"one" atom, at the position 0.00 0.00 0.00, and change "nat=1"
Please read about that in any solid state book.

Best

PhD. Arles V. Gil Rebaza
Instituto de Física de La Plata
La Plata - Argentine


2014-05-05 18:19 GMT-03:00 Ari P Seitsonen <Ari.P.Seitsonen at iki.fi>:

>
> 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
>>
>>
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-- 
###--------->   Arles V.   <---------###
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