Experimental and Computational (ab initio and DFT) Analysis of Vibrational Spectra of 2,6-Dimethyl-4-nitrophenol

The FT-IR and FT-Raman spectra of 2,6-Dimethyl-4-nitrophenol has been recorded in the range of 4000-100cm(-1). The fundamental mode of vibrational frequencies of compounds 26DM4NP is assigned. All the geometrical parameters have been calculated by using HF and DFT [B3LYP] methods with 6-311++G(d,p) basis set. Optimized geometries of the molecules have been interpreted and compared with the reported experimental values for substituted phenols. The harmonic and an harmonic vibrational wave numbers, IR intensities, Raman activities, reduced mass and force constants are calculated at the same theory level used in geometry optimization by the scaled vibrational frequencies at B3LYP/6-311++G(d,p) seems to coincide with the experimentally observed values with good agreement. The difference between observed and scaled wave number values of most of the fundamentals is very small in DFT and HF.