An approach to the aromaticity based on the energy of the occupied p orbitals

The studies performed during the last ten years on the possibility to determine an aromaticity criterion based on the energy of the occupied π orbitals has been described. The evolution of the research studies to obtain the D criterion defined as (Fourmula Presented) was described. The correlations between D and some other common aromaticity criteria have been presented showing a good relationship between D and other aromatic criteria; D values were used to determine some limits of other aromatic criteria. The role of both DFT functionals and basis sets has been discussed.