The low frequency phonons dynamics in supercooled LiCl, 6 H2O.
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.
Dipartimento di Chimica, Università di Perugia, I-06100 Perugia, Italy.
M E
ME
Gallina
L
L
Bove
C
C
Dreyfus
A
A
Polian
B
B
Bonello
R
R
Cucini
A
A
Taschin
R
R
Torre
R M
RM
Pick