STRUCTURE AND VIBRATIONAL SPECTROSCOPIC STUDIES OF 1-NAPHTHOL: DENSITY FUNCTIONAL THEORY CALCULATIONS

Abstract

In the SQM approach the systematic errors of the computed harmonic force field were corrected by a few scale factors which were found to be well transferable between chemically related molecules [2,7–9]. Recent spectroscopic studies on these materials have been motivated because the vibrational spectra are very useful for the understanding of specific biological process and in the analysis of relatively complex systems. In the present study, we extend a probing into the application of the B3LYP/6-31G* (small basis set) and B3LYP/6-311+G** (large basis set) based on SQM method [2] to vibrational analysis and conformational stability of 1-Naphthol. The main difficulty in such investigation is that the vibrational spectra of these compounds have not been completely analyzed until now and generally only rough assignments are available. The geometrical parameters of the most optimized geometry obtained via energy calculations were used for the DFT calculations. The infrared and Raman intensities were also predicted. Based on these calculations, the simulated FT-IR and FT-Raman spectra were obtained. The observed and the simulated spectra agrees well. Experimental Details The fine polycrystalline samples of 1-Naphthol were obtained from the Lancaster chemical company, UK, and used as such for the spectral measurements. The room temperature Fourier transform infrared spectra of the title compounds were measured in the 4000-400 cm �1 region at a resolution ±1cm �1 using KBr pellets on Perkin-Elmer RX1 FT-IR spectro photometer equipped with He-Ne laser source, KBr beam splitter and LiTaO 3 detector. Boxcar apodisation was used for the 250 averaged interferograms collected for both the samples