Hi:
I would like to know how to calculate the bulk cohesion energy of a crystalline
solid (in my case, Fe) with Siesta. I guess it is the difference between the
total energies of the atom in the bulk and the isolated atom.
Thanks,
Roberto
I would like to know how to calculate the bulk cohesion energy of a
crystalline solid (in my case, Fe) with Siesta. I guess it is the
difference between the total energies of the atom in the bulk and the
isolated atom.
Yes. But you have to do it with identical grid.
And also don't forget about
Yes. But you have to do it with identical grid.
And also don't forget about basis set superposition error (BSSE) corrections,
i.e. your single atom should have the ghost atoms around it in the same
geometry as in your bulk (nearest neighbors would be enough).
Ok, but, see, the bcc Fe unit
Ok, but, see, the bcc Fe unit (primitive) cell has only one atom. If I
include ghost atoms in the calculation of the isolated atom, I will have
a basis set in this case larger than that used for the bulk calculation.
You have to take a unit cell of ~10A for an isolated atom,
carefully adjust th
leksandr Voznyy <[EMAIL PROTECTED]>
To: SIESTA-L@listserv.uam.es
Sent: Saturday, November 1, 2008 12:31:52 AM
Subject: Re: [SIESTA-L] Bulk cohesion energy
> Ok, but, see, the bcc Fe unit (primitive) cell has only one atom. If I
> include ghost atoms in the calculation of the isolated a
I did like that:
E=E(Fe-bulk)-E(Fe-isolated)
and I obtained 4.80 eV
This doesn't mean anything yet. It's the same as fitting pseudopotential
to obtain better lattice constant.
So I think
that in this case the BSSE correction is negligible.
Try it before saying it. The single atom vs atom in
Where in the output can I find the number of basis functions?
Roberto
From: Oleksandr Voznyy <[EMAIL PROTECTED]>
To: SIESTA-L@listserv.uam.es
Sent: Monday, November 3, 2008 3:41:53 PM
Subject: Re: [SIESTA-L] Bulk cohesion energy
> I did like that:
s
Sent: Tuesday, November 4, 2008 9:45:34 AM
Subject: Re: [SIESTA-L] Bulk cohesion energy
Hi,
At the beginning of each SIESTA run, during the generation
of the atomic orbitals, the number of basis functions for each
species is written.
Best
Eduardo
On 03/11/2008, at 21:05, Roberto Veiga wrote:
Voznyy <[EMAIL PROTECTED]>
To: SIESTA-L@listserv.uam.es
Sent: Monday, November 3, 2008 3:41:53 PM
Subject: Re: [SIESTA-L] Bulk cohesion energy
> I did like that:
> E=E(Fe-bulk)-E(Fe-isolated)
> and I obtained 4.80 eV
This doesn't mean anything yet. It's the same as fit
ctions?
Roberto
From: Oleksandr Voznyy <[EMAIL PROTECTED]>
To: SIESTA-L@listserv.uam.es
Sent: Monday, November 3, 2008 3:41:53 PM
Subject: Re: [SIESTA-L] Bulk cohesion energy
> I did like that:
> E=E(Fe-bulk)-E(Fe-isolated)
> and I obtained 4.80 eV
This doesn't mean anything yet
uesday, November 4, 2008 1:33:54 PM
Subject: Re: [SIESTA-L] Bulk cohesion energy
Hola,
You sum the multiplication of the number of basis functions of each species by
the number of atoms of that species.
You should take into account more than the atoms explicitly defined in your
input.
Best,
Eduar
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