Low-frequency spectra in hydrophobic environment studied by terahertz time-domain spectroscopy

Abstract

Low-frequency spectrum of hydration water molecules around the hydrophobic probe in an aqueous solution has been obtained by using tetraalkylammonium cation as a probe and terahertz time-domain spectroscopy. The obtained spectrum of hydration water has intensity larger than that of ice and smaller than that of bulk water. This suggests that dynamics of hydration water molecules are partially restricted compared to those of bulk water.