Dear all,
I am performing calculations of anchoring mechanism of small
organic molecules on top of TiO2 surface.
I get that the Surface Formation Energy of every single surface is
different from theoretical results obtained at Plane Waves level but the
trend (the difference between the Surface Formation Energy of the various
reconstructions) agrees very well with those PW calculated results. I know
this is the expected behavior, and I am pretty satisfied of the fact that
such relative differences are in extremely good agreement with those PW
calculated.
Now, I now "attach" these small organic molecules on top of the surface
and similarly I find that the Adsorption Energy of the single mechanism is
far from that calculated at PW level, BUT here too the relative
differences
between various attacks, say the DeltaE(bidentate-monodentate),
DeltaE(monodentate-molecularly adsorbed) is in very good agreement with
the previously calculated at PW level (PWscf).
I wonder if this is the expectable behaviour.
Mind that I am calculating the BSSE corrections for all the cases.
Should the Adsorption Energy for each single attack be different from that
calculated at PW level?
Second brief question. Can I say that BSSE is negligible (almost) when
studying small cluster reactivity (for example, butane or propane reacting
with a metal oxide catalyst)?
Last...I am performing some NEB calculations with postprocessing tools
using SIESTA as geometry optimizer. Has anyone got experience with NEB
calculations? Could you in case suggest me a "safe" value for the
MeshCutoff? 100-120Ry could be a reasonable value?
Thanks a lot for the attention!
Very best regards,
Giacomo
--
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* Giacomo Giorgi *
* Assistant Professor *
* Research Center for Advanced Science and Technology (RCAST), *
* The University of Tokyo *
* 4-6-1, Komaba, Meguro-ku, Tokyo 153-8904, Japan *
* tel./fax: +81 3 5452 5442 *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
"Oltre le illusioni di Timbuctu'
e le gambe lunghe di Babalu' c'era questa strada...
Questa strada zitta che vola via come una farfalla,
una nostalgia, nostalgia al gusto di curacao...
Forse un giorno meglio mi spieghero'..."
(Paolo Conte, "Hemingway")
