On Thu, Aug 24, 2017 at 12:43:45AM +0100, Abderrahmane Reggad wrote: > The reason for my question is that I don't how does a DFT code work and I > want to know if the ionic state is a result or an assumption.
Abderrahmane, In a wien2k calculation you provide the number of electrons assigned to the core and to the valence regions of each chemical species in your system. However that is defining a population in orbital space. If the calculations proceeds appropiatelryi (convergence of results, convergence o basis set [k space], etc). The final distribution of the electrons should not be determined by your assumptions, so obtaining an ionic, covalent, metallic, magnetic, etc result should be a consecuence and not an assumption. However, you must examine the correctness of the calculation performing the analysis that is described in wien2k user guide (muffin tin radius, k vectors, ...) The analysis of the wien2k wavefunction and density can produce the approximate picture of a very ionic system (NaCl and MgO, for instance), a mostly covalent crystal (diamond and graphite, for instance), a metallic one (alkali metals), and so on. You can check all those examples in (sorry to describe my own publications, but those are things that I know quite well ;-) ) * Ions in crystals: The topology of the electron density in ionic materials. II. The cubic alkali halide perovskites V Luaña, A Costales, AM Pendás Physical Review B 55 (7), 4285 * A classification of covalent, ionic, and metallic solids based on the electron density P Mori-Sánchez, AM Pendás, V Luaña Journal of the American Chemical Society 124 (49), 14721-14723 * Non-nuclear maxima of the electron density on alkaline metals V Luaña, P Mori-Sánchez, A Costales, MA Blanco, AM Pendás The Journal of chemical physics 119 (12), 6341-6350 * Topological characterization of the electron density laplacian in crystals. The case of the group IV elements A Otero-de-la-Roza, V Luaña Journal of Chemical Theory and Computation 6 (12), 3761-3779 * Ions in Crystals: The Topology of the Electron Density in Ionic Materials. 4. The Danburite (CaB2Si2O8) Case and the Occurrence of Oxide− Oxide Bond Paths in Crystals V Luana, A Costales, P Mori-Sanchez, AM Pendás The Journal of Physical Chemistry B 107 (21), 4912-4921 _______________________________________________ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html