Yuhang,
A chemical reaction for your calculation would be the following:
24 Si -> Si_24
The binding energy is the energy absorbed by this reaction.
E_binding = SUM( products ) - SUM( reactants )
= E(Si_24) - 24*E(Si)
This is the total binding energy for your system.
Simply divide by the number of atoms, 24 in your case, to obtain the binding
energy per atom.
You have E(Si_24). It is the Total energy reported by Siesta, -2570.329449
All you need now is the Total energy of a single Si atom.
So, place a single Si atom in the same simulation cell you are using for the
Si_24 calculation.
Good luck,
Jason
On Thu, Nov 12, 2009 at 2:37 PM, yuhang jing <[email protected]> wrote:
> Hi, Siesta Users
>
> I try to calculate the binding energy of bulk silicon. The following
> is the results about the energy.
> siesta: Final energy (eV):
> siesta: Kinetic = 970.814378
> siesta: Hartree = 182.028830
> siesta: Ext. field = 0.000000
> siesta: Exch.-corr. = -779.962976
> siesta: Ion-electron = -1198.084510
> siesta: Ion-ion = -1745.125169
> siesta: Ekinion = 0.000000
> siesta: Total = -2570.329449
>
> I am confused. I do not know which one is the binding energy or is
> related to the binding energy. The cell contains 24 atoms. I think the
> binding energy should be about 4.63 eV/atom. However, I can not obtain
> it. Could you help me?
>
> Thanks a lot.
>
> --
> Yours Sincerely
> Yuhang Jing
>
