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.
Stefanutti, E., Bove, L.E., Alabarse, F.G., Lelong, G., Bruni, F., Ricci, M.A. (2019). Vibrational dynamics of confined supercooled water. THE JOURNAL OF CHEMICAL PHYSICS, 150(22), 224504 [10.1063/1.5094147].
Vibrational dynamics of confined supercooled water
Stefanutti E.;Bruni F.;Ricci M. A.
2019-01-01
Abstract
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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
