Hi
I calculated the binding energy of a cluster (species1) with a ligand(species
2) with this formula:
E_{total} - E_{species1} - E_{species2}
I run PAW in a cubic cell large enough to avoid periodicity effects in the
calculations (10 angstrom each side).
The geometry converges very well to a 2.1 angstrom distance between species, as
we expected.
However, the results are surprising from two respects.
First, the binding energy is too high. ~500 kcal/mol
Second, when I add new monomer to species2 (make a dimer), in principle, the
binding energy should remain constant (The bond length remains the same).
However, I get extra ~200kcal/mol in the energy.
The number of electrons:
cluster (species1): 499
monomer (species2): 60
dimer (species2): 102
So, something should be wrong with the formula or a scaling factor is needed
here.
I am wondering if you can guide me through this.
Best regards
Mohamad
?
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