If the anion stays charged, which is an issue by itself in DFT, the distance will never be large enough, because the slab will generate a macroscopic electric field. sb
___ Stefano Baroni, Trieste -- http://stefano.baroni.me > On 23 Feb 2021, at 07:05, Nam Tran <[email protected]> wrote: > > > Dear QE users, > > I would like to calculate the adsorption energy of a negative anion NO3- with > a positive slab (The total system is neutral). I cannot use the convention > formula Eds = E(slab+anion) - E(slab) - E(anion) because of the charge > compensation when calculating the energy of charged slab and charge > adsorbate. > > As the total system (slab+anion) is neutral, I wonder if it is possible to > just move the molecule far away from the slab (make sure that vacuum in > z-direction is large enough), and calculate the energy difference i.e., one > of them the molecule is far away from the surface and in the other one the > molecule adsorbed on the surface. > > > Best regards > Nam > > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu) > users mailing list [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users
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