THz dynamics of nanoconfined water by ultrafast optical spectroscopy
Year: 2017
Authors: Taschin A., Bartolini P., Torre R.
Autors Affiliation: European Lab Nonlinear Spect LENS, Via N Carrara 1, I-50019 Florence, Italy; Univ Florence, Dipartimento Fis Astron, Via G Sansone 1, I-50019 Florence, Italy.
Abstract: We investigated the vibrational dynamics and structural relaxation of water nanoconfined in porous silica samples with a pore size of 4 nm at different levels of hydration and temperature. We used the time-resolved optical Kerr effect (OKE), a spectroscopic technique that enables investigation of ultrafast water dynamics in a wide time (0.1-10 ps) or frequency (10-0.1 THz) window. At low hydration levels corresponding to two complete superficial water layers, no freezing occurs and the water remains mobile at all investigated temperatures. Meanwhile, at full hydration we witness a partial ice formation at about 248 K that coexists with the surface water remaining in the supercooled state. At low hydration, both structural and vibrational dynamics show significant modifications compared to bulk liquid water. This is due to the strong interaction of the water molecules with silica surfaces. Inner water, however, reveals relaxation dynamics very similar to bulk water.
Journal/Review: MEASUREMENT SCIENCE AND TECHNOLOGY
Volume: 28 (1) Pages from: 14009-1 to: 14009-8
More Information: The experiments have been realized in the LENS labs with the support of the Progetto Ateneo 2014 from the Dipartimento di Fisica ed Astronomia dell’Universita degli studi di Firenze and Ente Cassa di Risparmio di Firenze n. 2015/0822.KeyWords: nanoconfined water; supercooled phase; nanoporous glasses; time-resolved spectroscopyDOI: 10.1088/1361-6501/28/1/014009Citations: 5data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2024-10-20References taken from IsiWeb of Knowledge: (subscribers only)