Terahertz Spectroscopic Study of Vibrational Density of States in LiCl· 6H2O

We investigated two characteristic behaviors in the terahertz-band vibrational density of states of ${\mathrm {LiCl}} \cdot 6{\mathrm {H}}_{2}{\mathrm {O}}$ in the glassy state: a boson peak (BP) at 1 THz and a broad peak at approximately 2 THz. We succeeded in reproducing the behavior of the BP using heterogeneous elasticity theory, and extracted the nanomechanical properties. In addition, the broad peak at 2 THz is attributed to the bending mode between hydrogen-bonded water molecules, and the interaction between the BP and terahertz light was investigated.