Dear Jorg
Calculations of isolated atoms may sometimes be tricky.
Try to have a look at
/yourespresso/examples/example11
HTH
Giuseppe
On Thursday 21 July 2011 15:06:31 J?rg Buchwald wrote:
> Hello,
> I'm performing some first test-calculations with pwscf, where I try to
> get the binding energy of bulk silicon. The problem is, that the
> resulting energy, which should be the difference of the total
> energy of silicon crystal structure and the a free atom, is about 3eV
> too low. I used different pseudopotentials, different
> lattice-parameters and I also tested the convergencies (with k and
> the energy-cut-off) which worked, but I don't have a clue what a made
> wrong.
>
> Here are my Input files:
>
> ---
> &control
> prefix='silicon',
> pseudo_dir='/home/joerg/espresso-4.3.1/pseudo'
> outdir = '/home/joerg/scratch',
> /
> &system
> ibrav= 2, celldm(1) =10.263142, nat= 2, ntyp= 1,
> ecutwfc = 30.0,
> /
> &electrons
> /
> ATOMIC_SPECIES
> Si 28.086 Si.pbe-n-van.UPF
> ATOMIC_POSITIONS
> Si 0.00 0.00 0.00
> Si 0.25 0.25 0.25
> K_POINTS automatic
> 9 9 9 1 1 1
> ---
>
> and for the free atom:
>
> ---
> &control
> prefix='silicon',
> pseudo_dir='/home/joerg/espresso-4.3.1/pseudo'
> outdir = '/home/joerg/scratch',
> /
> &system
> ibrav= 0, celldm(1) =50.2, nat= 1, ntyp= 1,
> ecutwfc = 80.0,occupations='fixed',starting_magnetization(1)=10,
> /
> &electrons
> /
> ATOMIC_SPECIES
> Si 28.086 Si.pbe-n-van.UPF
> ATOMIC_POSITIONS
> Si 0.50 0.50 0.50
> K_POINTS gamma
>
> CELL_PARAMETERS {cubic}
> 1.00 0.00 0.00
> 0.00 1.00 0.00
> 0.00 0.00 1.00
> ---
>
> It would be nice if someone could help me.
> Thx & regards,
> J?rg Buchwald
>
>
> Leibniz-Institut fuer Oberflaechenmodifizierung e.V.
> Permoserstrasse 15
> 04318 Leipzig
> GERMANY
>
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? ?CNR - ISTITUTO DI STRUTTURA DELLA MATERIA ?
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