Chemical Reactivity by Variational Principles

7 UNIFICATION OF CHEMICAL REACTIVITY PRINCIPLES 3.7.1 CHEMICAL REACTIVITY BY VARIATIONAL PRINCIPLES 

There is wild recognized that in physical sciences the total energy variation 

Therefore, it seems that the variational physical principle of Eq. (3.534) do not suffice in order the chemical principles of electronegativity and chemical hardness being encompassed, as above stipulated, see Eqs. (3.346) and (3.347). As a consequence one is forced to perform the double variational procedure on the total energy, i.e., through applying the additional differentiation on physical energy expansion (3.535), within die so called chemical variational mode (and denoted as []) where the total differentiation will be taken only over the scalar-global (extensive x, nd 

the chemical variational principle applied to Eq. (3.536) will look like 

In conditions of chemical reactivity or binding certain amount of charge transfer and the system s potential fluctuations (departing from equilibrium) are involved 

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