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<div>Dear all,
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<p style="margin-top:0; margin-bottom:0">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:</p>
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E<sub>surface + adsorbate </sub>= <span>-4301.05337244</span>
<p style="margin-top:0; margin-bottom:0">E<sub>surface </sub>= <span>-4258.9387474</span><br>
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<p style="margin-top:0; margin-bottom:0">E<sub>adsorbate </sub>= <span>-42.37757742</span><br>
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<p style="margin-top:0; margin-bottom:0">So E<sub>ads </sub>= <span>E<sub>surface + adsorbate</sub></span> - (E<sub>surface
</sub>+ E<sub>adsorbate</sub>) = 0.26<br>
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<p style="margin-top:0; margin-bottom:0">Now this seems wrong. If E<sub>ads</sub> 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.</p>
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<p style="margin-top:0; margin-bottom:0">Thanks in advance,</p>
<p style="margin-top:0; margin-bottom:0">Laurens Siemons</p>
<p style="margin-top:0; margin-bottom:0">Master student chemistry</p>
University of Antwerp</div>
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