Dear Ari,
Any other papers you can provide relating to this problem would be extremely
useful. Thank you very much.
Best Wishes,
Jack Davis
On 15 Nov 2013, at 21:18, Ari P Seitsonen <Ari.P.Seitsonen at iki.fi> wrote:
Dear Jack Davis,
It is well known in the community that this is not a very accurate approach to
calculate the surface energy, even if in principle correct (or, even the
definition): You should at least make sure that the bulk is calculated along
the (111) direction with the same k point sampling. Only if you are very well
converged with the k point sampling in both the slab and bulk you might get a
converged value. A classic article discussing this problem is
Vincenzo Fiorentini and M Methfessel 1996 J. Phys.: Condens. Matter 8 6525
doi:10.1088/0953-8984/8/36/005
"Extracting convergent surface energies from slab calculations"
I can also try to find some more recent references if you wish.
Greetings from Zurich,
apsi
-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
Ari P Seitsonen / Ari.P.Seitsonen at iki.fi<mailto:Ari.P.Seitsonen at iki.fi>
/ http://www.iki.fi/~apsi/
Physikalisch-Chemisches Institut der Universitaet Zuerich
Tel: +41 44 63 54 497 / Mobile: +41 79 71 90 935
On Fri, 15 Nov 2013, Jack Davis wrote:
Dear Forum,
I?m trying to calculate surface energies using PWscf, however, I am unsure of
the methodology. To begin with we calculate the bulk energy of the FCC unit
cell, using the attached input. We then calculate the energy of a 111 slab, 10
layers thick with a 6 atom vacuum gap. The surface energy is then calculated as,
Surface energy = Energy of slab - (bulk energy * 10) / 2.
I think I am probably misunderstanding the energies PWscf is giving me. We?re
getting some strange answers!
Thank you,
Jack Davis
School of Chemistry
University of Birmingham
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