Absorption spectra of liquid water and aqueous buffers between 0.3 and 3.72 THz.

We have developed a terahertz absorption spectrometer suitable for strongly absorbing liquids such as water, and have precisely measured the absorption spectrum of water between 0.3 and 3.72 THz (10-124 cm(-1)). We have also examined the absorption spectra of aqueous 50 mM potassium phosphate buffers at pH 3 and 8, and find that they do not differ significantly from pure distilled de-ionized water.