title: Compactness aromaticity of atoms in molecules.
abstract: A new aromaticity definition is advanced as the compactness formulation through the ratio between atoms-in-molecule and orbital molecular facets of the same chemical reactivity property around the pre- and post-bonding stabilization limit, respectively. Geometrical reactivity index of polarizability was assumed as providing the benchmark aromaticity scale, since due to its observable character; with this occasion new Hydrogenic polarizability quantum formula that recovers the exact value of 4.5 a(0) (3) for Hydrogen is provided, where a(0) is the Bohr radius; a polarizability based-aromaticity scale enables the introduction of five referential aromatic rules (Aroma 1 to 5 Rules). With the help of these aromatic rules, the aromaticity scales based on energetic reactivity indices of electronegativity and chemical hardness were computed and analyzed within the major semi-empirical and ab initio quantum chemical methods. Results show that chemical hardness based-aromaticity is in better agreement with polarizability based-aromaticity than the electronegativity-based aromaticity scale, while the most favorable computational environment appears to be the quantum semi-empirical for the first and quantum ab initio for the last of them, respectively.
authors.affiliation: Chemistry Department, West University of Timişoara, Romania. mvputz@cbg.uvt.ro
authors.forename: Mihai V
authors.initials: MV
authors.lastname: Putz
mesh_terms: D006841:Hydrocarbons, Aromatic / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D008962:Models, Theoretical; D011789:Quantum Theory
chemical_list: D006841:Hydrocarbons, Aromatic; D006859:Hydrogen