Theoretical and experimental studies of vibrational spectra and thermodynamical analysis of 3'-bromopropiophenone and 4'-bromo-3-chloropropiophenone.

Quantum chemical calculations of molecular geometries, vibrational wavenumbers and thermodynamical properties of 3'-bromopropiophenone and 4'-bromo-3-chloropropiophenone were carried out using Hartree-Fock (HF) and density functional theory (DFT) using hybrid functional B3LYP with 6-31 G (d,p) as basis set. The optimized geometrical parameters obtained by HF and DFT calculations are in good agreement with the experimental FTIR and FT Raman spectral datas. The observed and the calculated frequencies are found to be in good agreement. The experimental spectra also coincide satisfactorily with those of theoretically constructed simulated spectrograms.