Theoretical and experimental studies of the vibrational spectra of m-methylaniline

The FT-IR and FT-Raman spectra of m-methylaniline (mMA) have been recorded. Optimized molecular structures and normal vibrations of mMA have been obtained from the ab initio-HF and the DFr-B3LYP levels. The 6-31G* basis set has been used for each level of calculations. Correction factors, which bring computational frequencies in closer agreement with the experimental data, have been calculated for predominant vibrational motions of the normal modes at each level of theory. All IR and Raman bands of mMA have been assigned in the frameworks of the calculations. The assignments have been compared each other and with the 30 benzene-like modes. The DFr-B3LYP/6-31G* calculations have been found more reliable than the ab initio-MP2/6-31G* calculations for the vibrational study of mMA. (C) 2003 Published by Elsevier Science B.V.