Hi Pablo,
The binding energy of the Fluorine, BSSE corrected, would be:
\Delta E_{ads}^C = E(tube/[ads])+E([tube]/ads)-E(tube/ads)
where the [] indicate that what is inside them must have ghost orbitals.
That is, tube/[ads] means that the tube's orbitals are present, but the
orbitals for the adsorbate (the fluorine) are ghosts. That is, you have to
always include the ghosts, at the equilibrium geometry that you got by
relaxing the system. BSSE corrections yield adsorption energies that are
very close to those of plane-wave calculations, if the parameters of your
calculations are good enough.
Cheers,
Marcos
Vous avez écrit / You have written / Lei ha scritto / Você escreveu...
Pablo Denis
> Dear siesta users,
>
> I am a little confused about how i must
> compute the binding energies between an atom
> and a nanotube. Lets say that we add a
> fluroine atom to a SWCNT:
>
> F+ SWCNT --> F-SWCNT
>
> we can compute the energy change = E(F-SWCNT) - E(F) - E(SWCNT)
>
> however, if one wants to include the BSSE correction, the energy of the
> tube E(SWCNT) is strongly affected if we take into account the deformation
> of the geometry caused by the new bond.
>
> energy change with BSSE = E(F-SWCNT) - E(F+ basis of SWCNT) - E(SWCNT +
> BASIS of F at the geometry of the complex)
>
> Thus after BSSE correction the binding energy can larger than the result
> obtained without BSSE correction if the deformation of the tube is strong.
>
> I will appreciate some comments from the siesters... which is the correct
> procedure if there is one, and which result is closer to the plane waves
> ones.
>
> Many thanks.
>
> Regards,
>
> pablo
--
Dr. Marcos Verissimo Alves
Post-Doctoral Fellow
Unité de Physico-Chimie et de Physique des Matériaux (PCPM)
Université Catholique de Louvain
1 Place Croix du Sud, B-1348
Louvain-la-Neuve
Belgique
------
Gort, Klaatu barada nikto. Klaatu barada nikto. Klaatu barada nikto.
