Gallina M E, Bove L, Dreyfus C, Polian A, Bonello B, Cucini R, Taschin A, Torre R, Pick R M
Dipartimento di Chimica, Università di Perugia, I-06100 Perugia, Italy.
J Chem Phys. 2009 Sep 28;131(12):124504. doi: 10.1063/1.3197851.
We report the results of a series of ultrasound, Brillouin scattering, and optical heterodyne detected transient grating experiments performed on a LiCl, 6H(2)O solution from room temperature down to the vicinity of its liquid-glass transition, T(g) approximately 138 K. Down to T approximately 215 K, the supercooled liquid has a behavior similar to what is expected for supercooled water: its zero frequency sound velocity, C(0), continuously decreases while the corresponding infinite frequency velocity, C(infinity), sharply increases, reflecting the increasing importance of H bonding when temperature is lowered. Below 215 K, specific aspects of the solution, presumably related to the role of the Li(+) and Cl(-) ions, modify the thermal behavior of C(0), while a beta relaxation process also appears and couples to the sound propagation. The origin of those two effects is briefly discussed.
我们报告了一系列对LiCl·6H₂O溶液进行的超声、布里渊散射和光外差检测瞬态光栅实验的结果，实验温度范围从室温降至其液-玻璃转变温度附近，T(g)约为138K。在T约为215K以下，过冷液体的行为与过冷水预期的行为相似：其零频声速C(0)持续降低，而相应的无限频声速C(∞)急剧增加，这反映出温度降低时氢键作用的重要性不断增加。在215K以下，溶液的特定方面，可能与Li⁺和Cl⁻离子的作用有关，改变了C(0)的热行为，同时还出现了一个β弛豫过程并与声传播耦合。简要讨论了这两种效应的起源。
