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Hi <br>
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I calculated the binding energy of a cluster (species1) with a ligand(species 2) with this formula:<br>
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E_{total} - E_{species1} - E_{species2}<br>
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<br>
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I run PAW in a cubic cell large enough to avoid periodicity effects in the calculations (10 angstrom each side).<br>
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The geometry converges very well to a 2.1 angstrom distance between species, as we expected.<br>
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However, the results are surprising from two respects.<br>
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First, the binding energy is too high. ~500 kcal/mol<br>
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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).</div>
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However, I get extra ~200kcal/mol in the energy.<br>
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The number of electrons:<br>
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cluster (species1): 499<br>
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monomer (species2): 60<br>
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<font face="Calibri,Arial,Helvetica,sans-serif" size="2"><span style="font-size: 16px;">dimer (species2): 102<br>
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<font face="Calibri,Arial,Helvetica,sans-serif" size="2"><span style="font-size: 16px;">So, something should be wrong with the formula or a scaling factor is needed here.<br>
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<font face="Calibri,Arial,Helvetica,sans-serif" size="2"><span style="font-size: 16px;">I am wondering if you can guide me through this.<br>
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<font face="Calibri,Arial,Helvetica,sans-serif" size="2"><span style="font-size: 16px;"><br>
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<font face="Calibri,Arial,Helvetica,sans-serif" size="2"><span style="font-size: 16px;">Best regards<br>
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<font face="Calibri,Arial,Helvetica,sans-serif" size="2"><span style="font-size: 16px;">Mohamad<br>
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