IMPACT OF SOLVENT POLARITY AND SUBSTITUENTS ON POLYCYCLIC AROMATIC HYDROCARBONS’ EMISSION AND ABSORPTION SPECTRUMS

Abstract

The Ultraviolet absorption spectra and emission spectrum of polycyclic aromatic hydrocarbons (PAHs) are studied at different solvents i.e. acetone, hexane, dimethyl sulfoxide, ethyl acetate, of varying polarity. The effect of amino substituents at naphthalene and Anthracene have also been investigated. The solvent polarity impacts the absorption maxima and intensity maxima of emission spectra by change in physiochemical properties of solvent like dipole moment, charge transfer, H-bonding. The relation between absorption wavelength and emission intensity with solvent polarity indicates that there are solute solvent interactions in the prepared solution. The orientation polarizability was associated with bathochromic or hypsochromic shift and Stoke’s shift. The effect of solvents on the absorption band shifts reflects how much charge of solute particles are reorganized in response to electrical stimulation. The nature of substituents also influences the emission and absorption spectrum. These co-relations are studied in detail in this project. The emission and absorption spectrum of PAHs in 3 varying polarity solvents are in accordance with the previously reported results.