Raman spectroscopic and ab initio studies on the molecular interactions in the binary liquid mixtures of 4'-fluoroacetophenone.

Raman spectral measurements were carried out for binary liquid mixtures 4'fluoroacetophenone (4F) in different volume concentration ranges at a regular intervals of 0.1 in different solvents. The asymmetric Raman peak observed at 1685 cm(-1) (carbonyl stretching mode) in pure 4F confirms the presence of self association in 4F. The optimization was performed for monomer and dimer structures of 4F as well as 4F dimer with solvents using Gaussian 03 W package. Vibrational wavenumber calculation was performed for monomer and dimer structures of 4F to explain the experimentally observed Raman spectra. The carbonyl stretching mode is the more polar group and its interaction with the solvent molecule plays a vital role in determining the physical and chemical properties of the solute. Hence the observed variation in the peak position and linewidth of carbonyl stretching mode was analysed as a result of intermolecular interactions between the solute and the solvent molecules. Also, interaction energies were calculated to support the results obtained from Raman spectra.