Dear Mostafa Y. thanks for the useful informations
2015-07-19 5:29 GMT+03:00 Mostafa Youssef <myous...@mit.edu>: > Dear Bahadir > > First, charged slabs are problematic because their total energy does not > converge with respect to vacuum thickness. You can test on a simple model. > However, there is a trick to go around this by inserting a dopant far a way > from the critical reaction zone. For example suppose you want to study +1 > charged defect on ZrO2 surface. Then you can insert one Y ion(typically 3+ > and hence -1 with respect to Zr4+) . This should generate a positive > charge somewhere else in the slab and one hopes that this positive charge > will localize correctly where you expect it to localize. But one has to be > cautious because this also generates a large dipole across the slab. One > way to go around this by symmetrizing the slab such that dipoles cancel. > > > Second, even if charged slabs work, I think you are not conserving the > charge when you calculate the binding energy. Because you mentioned you > used tot_charge=-1 in the slab+molecule , slab only, molecule only. To me > this will not conserve the charge when you calculate the binding energy > (B.E.) > > B.E. =(slab+molec.) - (slab) - (molec) > > Although I have seen papers defining binding energies that do not conserve > the charge, I do not think this is meaningful. > > Mostafa Y. > MIT > > _______________________________________________ > Pw_forum mailing list > Pw_forum@pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum >
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