Quantum Mechanical study for vibration Frequencies C - C bonds for Benzo [J] Fluoranthene molecule, positive and negative radical Ions

The chemistry of polyaromatic hydrocarbons (PAHs) is gaining increasing importance due to their carcinogenic properties and their presence in interstellar spaces [1]. They could become potential starting materials for petrochemical industries, being a significant component of the heavy fractions of earth oils [2]. For these reasons considerable efforts were made to study their chemical and physical properties [1], e. g. IR spectroscopic studies also on their radical cations. Benzo [J] Fluoranthene (Fig. 2), is a prominent member of the PAH family, for which IR spectroscopic studies were done. Measurements were done for its radical cation and anion in the isolated matrix [3], as well as ab initio theoretical studies [4]. However a complete normal coordinate analysis on the symmetry and the valence basis of all its 3N-6 vibration modes is still missing. Benzo (J) fluoranthene is present as a component of polycyclic aromatic hydrocarbons (PAH) content in the environment usually resulting from the incomplete combustion or pyrolysis of organic matters, especially fossil fuels and tobacco.