Theoretical Study of Vibration Spectroscopy for Neutral and Charged Fluoranthene Molecule


The vibration frequencies and infrared absorption intensities for the fluoranthene molecule (C16H10) and their positive and negative radical ions have been calculated using ab initio method according to the density functional theory (DFT) at the B3LYP / 6-311G basis set, in addition to PM3 semi-empirical quantum chemical method. Although, the importance of this molecule due to their presence in interstellar space and their environmental contaminating properties, the literatures miss to a complete classification for (3N-6) vibration modes and the vibration frequencies and infrared absorption intensities calculations for the negative radical ion. For these reasons our calculation and classification considered to be assignment. All calculated vibration frequencies rearrangement as the Hertzberg convention, then classified symmetrically and assigned by valence for (3N-6) modes depending on graphical pictures obtained by using Hyperchem program. Generally, the calculated vibration frequencies values showed a good agreement and compatible with values measured experimentally and those calculated by other theoretical methods.