[Wien] Formation energy of a deffective lattice

[Ricardo Faccio]

Hi  

    I'm performing calculations for defective supercells.   

The formation energy for a system could be=   

E(defect_formation)=E(defective)-[E(bulk)+E(isolated_atom)].   

    My problem is related with the total energy for an isolated atom, Wien take as a reference the average potential of the supercell, but how to deal with it in the case of a single atom. So, how can I perform a calculation for an isolated atom in order to be considered in the previous formula?  

    Thanks in advance  

Ricardo

-------------------------------------------------------------------------
-----   Ing. Quím. Ricardo Faccio
 
  Mail: Cryssmat-Lab., Cátedra de Física, DETEMA
  Facultad de Química, Universidad de la República
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  E-mail: rfaccio at fq.edu.uy
  Phone: 598 2 9241860 Int. 109
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  Fax:    598 2 9241906
  Web:  http://cryssmat.fq.edu.uy/ricardo/ricardo.htm
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