Let us look at the set of parameters obtained from the quantum-chemical calculations: IP, EA, electronegativity χ (Equation ), hardness η (Equation ), and also the dissociation energies of the neutral molecule into two equivalent molecular fragments according to Figure . The resulting trends as a function of the number of carbon atoms in the molecule are given in Figure . The IP decreases and EA increases with an increasing number of carbon atoms. However, their mean value (χ) remains rather constant, as predicted with Hückel's method. This means that our approximation, resulting in Equation , applies to this type of system.