Dynamic Crossover in Supercooled Confined Water: Understanding Bulk Properties through Confinement

• Published in: The journal of physical chemistry letters Vol. 1; no. 4; pp. 729 - 733
• Main Authors: Gallo, P, Rovere, M, Chen, S.-H
• Format: Journal Article
• Language: English
• Published: American Chemical Society 18.02.2010
• Subjects: Statistical Mechanics, Thermodynamics, Medium Effects
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/jz9003125

We present here molecular dynamics simulations of deeply supercooled SPC/E water confined in a cylindrical pore of MCM-41 silica material. By a layer analysis of the tag particle density correlators, we are able to extract the α-relaxation time of the mobile portion of the confined water. This relaxation time is the same as what can be extracted from neutron scattering experiments. From examination of the temperature-dependent behavior of the relaxation time and the dynamic susceptibility, we locate a dynamic crossover at T = (215 ± 5) K and a corresponding peak in the specific heat, in agreement with experimental findings in confined water and simulations of the bulk water. Our study demonstrates that the recent results of the experiments on confined water are extremely relevant for the comprehension of low-temperature bulk properties of water.