Anomalous diffusion of water molecules at grain boundaries in ice I-h

Author(s)

Franco Pinheiro Moreira, Pedro Augusto ^[1] ; de Aguiar Veiga, Roberto Gomes ^[2] ; Ribeiro, Ingrid de Almeida ^[3] ; Freitas, Rodrigo ^{[4, 5]} ; Helfferich, Julian ^[6] ; de Koning, Maurice ^{[3, 7]}

Affiliation

^[1] Univ Fed Sao Carlos, Dept Fis, Rodovia Washington Luiz, Km 235, CP 676, BR-13565905 Sao Carlos, SP - Brazil

^[2] Univ Fed ABC, Ctr Engn Modelagem & Ciencias Sociais Aplicadas, BR-09210580 Santo Andre, SP - Brazil

^[3] Univ Estadual Campinas, UNICAMP, Inst Fis Gleb Wataghin, BR-13083859 Campinas, SP - Brazil

^[4] Lawrence Livermore Natl Lab, Livermore, CA 94550 - USA

^[5] Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 - USA

^[6] Karlsruhe Inst Technol, Inst Nanotechnol, D-76344 Eggenstein Leopoldshafen - Germany

^[7] Univ Estadual Campinas, UNICAMP, Ctr Computat Engn & Sci, BR-13083861 Campinas, SP - Brazil

• Document type: Journal article
• Source: Physical Chemistry Chemical Physics; v. 20, n. 20, p. 13944-13951, MAY 28 2018.
• Web of Science Citations: 2

Abstract

Using ab initio and classical molecular dynamics simulations, we study pre-melting phenomena in pristine coincident-site-lattice grain boundaries (GBs) in proton-disordered hexagonal ice I-h at temperatures just below the melting point T-m. Concerning pre-melt-layer thicknesses, the results are consistent with the available experimental estimates for low-disorder impurity-free GBs. With regard to molecular mobility, the simulations provide a key new insight: the translational motion of the water molecules is found to be subdiffusive for time scales from approximate to 10 ns up to at least 0.1 s. Moreover, the fact that the anomalous diffusion occurs even at temperatures just below T-m where the bulk supercooled liquid still diffuses normally suggests that it is related to the confinement of the GB pre-melt layers by the surrounding crystalline environment. Furthermore, we show that this behavior can be characterized by continuous-time random walk models in which the waiting-time distributions decay according to power-laws that are very similar to those describing dynamics in glass-forming systems. (AU)

• FAPESP's process: 10/13902-4 - Study of martensitic phase transitions in metallic alloys
• Grantee: Rodrigo Moura Freitas
• Support type: Scholarships in Brazil - Master
• FAPESP's process: 16/23891-6 - Computer modeling of condensed matter
• Grantee: Alex Antonelli
• Support type: Research Projects - Thematic Grants
• FAPESP's process: 14/10294-4 - Multiscale computational modeling of the microstructural evolution and plasticity in metallic alloys
• Grantee: Roberto Gomes de Aguiar Veiga
• Support type: Research Grants - Young Investigators Grants
• FAPESP's process: 13/08293-7 - CCES - Center for Computational Engineering and Sciences
• Grantee: Munir Salomao Skaf
• Support type: Research Grants - Research, Innovation and Dissemination Centers - RIDC