Vibrational spectra of nucleosides studied using terahertz time-domain spectroscopy

We demonstrate that terahertz (THz) time-domain spectroscopy is a powerful technique for measuring temperature-dependent and spatially-resolved vibrational spectra in the frequency range 0.2–3.0 THz. A number of well resolved absorption peaks are observed for polycrystalline nucleosides, and we have mapped the evolution of these absorption features continuously between 4 and 295 K. The resonance frequency is found to shift with temperature and an empirical expression describing this frequency shift is given. In addition, we present spectrally-resolved THz images based on these vibrational modes, accessing both spatial and compositional information of subsurface biochemical materials. # 2003 Elsevier B.V. All rights reserved.