Vibrational spectroscopy of xanthoxyline crystals and DFT calculations

The Fourier transform infrared and Fourier transform Raman spectra of xanthoxyline crystals are reported, along with ab initio computations of the vibrational spectrum of the xanthoxyline molecule. The infrared and Raman spectra were recorded at 300 K in the 400- to 4,000- and 40- to 4,000-cm⁻¹ intervals, respectively. The vibrational wave numbers and wave vectors were obtained from a density functional computation with the 6-31 G(d,p) basis set and the B3LYP approximation to the exchange correlation functional. Comparison with the theoretical results allows assignment of normal modes to the prominent features of the recorded spectra. (author)