Average Local Ionization Energies of Atoms

Fricke has pointed out that there is a reasonably good inverse correlation between ionization energy and polarizability for the atoms H-Ra [8]. This led us to investigate whether there is a relationship between a and i(r) [9]. For this purpose we evaluated I(r) on the surface of each of the atoms He-Kr, the surface being defined either as (a) the spherical shell enclosing 98% of the electronic charge [14], or (b) the 0.001 au contour of the electronic density [15], By either approach, a and I(r) were found to obey an equation of the form [9], 

Finally, Nagy, Parr and Liu have demonstrated similarities, for a group of atoms, between the radial variation of I(r) and that of the local temperature, T(r) (16). The latter is defined in terms of the kinetic energy per electron at the point r [17]. In particular, T(r) also decreases in an approximately stepwise fashion, and the steps occur at about the same points as for I(r). 

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Politzer P, Murray JS, Grice ME, Brinck T, Ranganathan S (1991) Radial behavior of the average local ionization energies of atoms. J. Chem. Phys. 95 6699-6704... 

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