Vibrational analysis, ab initio HF and DFT studies of 2,4,6-trimethyl phenol

Abstract

The Fourier transform infrared (FTIR) and FT-Raman spectra of 2,4,6-trimethylphenolhave been recorded in the range 4000–400 and 3500–100 cm^-1, respectively. The complete vibrational assignment and analysis of the fundamental modes of the compound have been carried out using the observed FTIR and FT-Raman data. The vibrational frequencies determined experimentally have been compared with those obtained theoretically from ab initio HF and DFT-B3LYP gradient calculations employing 6-31+G (d,p) basis sets for the optimized geometries of the compound. The geometries and normal modes of vibration obtained from the HF and DFT methods are in good agreement with the experimental data. The normal coordinate analysis has also been carried out with ab initio force fields utilizing Wilson’s FG matrix method. The interactions of the skeletal vibrational modes have been investigated.