not necessarily, if there is a barrier (after all, there are plenty of exothermic chemical reactions, without which no fire would exist!) — Stefano B
> On 8 Mar 2018, at 15:50, Laurens Siemons <[email protected]> wrote: > > Dear all, > > I'm calculating parameters like adsorption energy, geometric parameters, NMR > chemical shifts of adsorbates on a surface. In this specific case I > calculated the adsorption energy of an ethyl anion on an anatase 001 surface > of titania. I got the following energies: > > Esurface + adsorbate = -4301.05337244 > Esurface = -4258.9387474 > Eadsorbate = -42.37757742 > > So Eads = Esurface + adsorbate - (Esurface + Eadsorbate) = 0.26 > > Now this seems wrong. If Eads is positive, so adsorption is not favourable, > then the ethyl-anion should migrate away from the surface in the relax > calculation of a001cti. correct? I executed the three calculations with the > exact same parameters as the other ones so I don't see how this is possible. > I attached my input files of the calculations. I hope someone can guide me > through this. > > Thanks in advance, > Laurens Siemons > Master student chemistry > University of Antwerp > > <a001cti.rx.in><anatase001-2x2-4.rx.in><ethyl-anion.rx.in>_______________________________________________ > users mailing list > [email protected] <mailto:[email protected]> > https://lists.quantum-espresso.org/mailman/listinfo/users > <https://lists.quantum-espresso.org/mailman/listinfo/users> — Stefano Baroni - SISSA, Trieste - http://stefano.baroni.me, stefanobaroni (skype) There are two ways of doing a theoretical calculation: you should have either a clear physical model in mind, or a rigorous mathematical basis. You have neither. [E. Fermi to F.J. Dyson, as humbly reported by the latter]
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