Local ionicity - an alternative definition for ab initio calculations

Alternative general definitions of ionicity and ionic radii based on the ch arge density null-flux concept are introduced. This method is local in natu re and possible to adapt to any atom in any physical system including surfa ces, interfaces, defects and alloys. These and other explicit advantages, a s compared to the standard approaches, are discussed in detail. The current approach is especially suitable for density functional methods, and is app lied to a number of m-V semiconductors, alkali halides and a few alkaline e arth compounds. Good agreement with traditional results is found.