Eur. Phys. J. E (2011) 34: 126
https://doi.org/10.1140/epje/i2011-11126-4

Regular Article

Structure of supercooled water in clusters and bulk and its relation to the two-state picture of water: Results from the TIP4P-ice model

¹⁹⁶⁶⁵ Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón II, Ciudad Universitaria, C1428EGA, Buenos Aires, Argentina
²⁹⁶⁶⁵ Área de Fisicoquímica, Departamento de Química and INQUISUR-UNS-CONICET, Universidad Nacional del Sur, Avenida Alem 1253, 8000-Bahía Blanca, Argentina
³⁹⁶⁶⁵ Department of Biomedical Engineering and Chemistry of Life Processes Institute, Northwestern University, 2145 Sheridan Rd, IL 60208, Evanston, USA
⁴⁹⁶⁶⁵ Departamento de Física de Materia Condensada, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica (CNEA), B1650KNA San Martín, Buenos Aires, Argentina

^* e-mail: rodriguezfris@plapiqui.edu.ar

Received: 8 July 2011
Accepted: 2 November 2011
Published online: 24 November 2011

Abstract

The structure of water clusters (H₂O)_n (n = 40 -200) and bulk water were examined by molecular dynamics simulations using the TIP4P-ice water model. The analysis of the low-temperature structures in terms of the local structure index (LSI) showed a bimodal distribution. This finding supports the two-state picture derived from the analysis of the inherent dynamics of bulk SPC/E water. The water molecules at the outer interface of the coldest clusters are more structured than those in the inner core. The geometrical constraint of the interface forces the surface molecules to lose one neighbor and adopt a local angular distribution of hydrogen bonds resembling that found in the basal plane of ice Ih.