Absolute electronegativity and hardness: An analogy with classical electrostatics suggests an interpretation of the Parr 'electrophilicity index' as a 'global energy index' leading to the 'minimum electrophilicity principle'

The quantity ω = 1/2 χ2/η, (χ electronegativity, η absolute hardness) decreases in some basic exothermal processes. Its variation in the transformation A+B→AB is correlated to the bond energy of AB.