Vibrational dynamics of confined supercooled water

E. Stefanutti (1, 2) , L. Bove (1) , Frederico Alabarse (1) , G. Lelong (1) , F. Bruni (2) , M. A Ricci (2)

1 IMPMC - Institut de minéralogie, de physique des matériaux et de cosmochimie
2 ROMA TRE - Università degli Studi Roma Tre = Roma Tre University

The quest for a possible liquid-liquid coexistence line in supercooled water below its homogeneous nucleation temperature is faced by confining water within a porous silica substrate (MCM-41). This system is investigated by synchrotron radiation infrared spectroscopy, exploring both the intramolecular and the intermolecular vibrational dynamics, in the temperature range from ambient down to ∼120 K, along several isobaric paths between 0.7 kbar and 3.0 kbar. Upon lowering the temperature, the OH-stretching band shows that the intramolecular vibrational dynamics continuously evolves from predominantly liquidlike to predominantly icelike. An abrupt change in the line shape of the intermolecular vibrational band between 220 K and 240 K, depending on the pressure, is the signature of nucleation of ice within the MCM-41 pores. These findings do not support the presence of two liquid phases and provide evidence for the coexistence of liquid water and ice in water confined in MCM-41.

Mots clés: Phase transitions; Infrared spectroscopy; Crystallography; Mesoporous material; Synchrotron radiation; Glass; Chemical bonding

Domaines: Chimie-Physique [physics.chem-ph]; Chimie théorique et/ou physique

E. Stefanutti, L. Bove, Frederico Alabarse, G. Lelong, F. Bruni, et al.. Vibrational dynamics of confined supercooled water. Journal of Chemical Physics, 2019, 150 (22), pp.224504. ⟨10.1063/1.5094147⟩. ⟨hal-02173067⟩