FTIR and Raman spectra and SQM force field calculation for vibrational analysis of 2,3,4- and 2,3,6-tri-fluoro-anilines

Raman and FTIR spectra for 2,3,4- and 2,3,6-tri-fluoro-aniline molecules have been recorded in the wavenumber regions 50–4000 and 400–4000 cm−1 respectively. Measurement of depolarization ratios for the Raman lines for both the molecules has also been made. The HF with the basis set 6-31++G(d,p) and DFT with the basis sets 6-31++G(d,p) and 6-311++G(d,p) have been employed to carry out the molecular geometries, atomic charges and vibrational frequencies along with their IR and Raman intensities. Normal coordinate analysis method has also been employed to carry out the potential energy distributions (PEDs). The assignment of each normal mode has been made using observed and calculated frequencies, their IR and Raman intensities, depolarization ratios for the Raman lines and PEDs. The influences of fluorine atoms towards the geometries and normal modes of the aniline molecule have been discussed.