Direct visualization of molecular stacking in quasi-2D hexagonal ice

Yangrui Liu; Yun Li; Jing Wu; Xinyu Zhang; Pengfei Nan; Pengfei Wang; Dapeng Sun; Yumei Wang; Jinlong Zhu; Binghui Ge; Joseph S. Francisco

arXiv · 2312.08073

Direct visualization of molecular stacking in quasi-2D hexagonal ice

Yangrui Liu·Yun Li·Jing Wu·Xinyu Zhang·Pengfei Nan·Pengfei Wang·Dapeng Sun·Yumei Wang·Jinlong Zhu·Binghui Ge·Joseph S. Francisco

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Abstract

The structure and properties of water or ice are of great interest to researchers due to their importance in the biological, cryopreservation and environmental fields. Hexagonal ice (Ih) is a common ice phase in nature and has been extensively studied; however, microstructural investigations at the atomic or molecular scale are still lacking. In this paper, the fine structure of quasi-2-dimensional ice Ih films was directly examined using cryogenic transmission electron microscopy. Two types of thin Ih films were observed: perfect single crystals growing along the [0001] direction and crystals with stacking faults, including both basal (BSF) and prismatic (PSF) ones, along the orientation of [11-20]; these results were further confirmed by theoretical calculations. Importantly, for the first time, the stacking faults in ice Ih were directly visualized and resolved. In light of the extension behavior of the chair conformation composed of the water molecules, we elucidated the formation mechanism of BSF in Ih, namely, the Ic phase. This study not only determined the structural characteristics of ice structure at the molecular scale but also provided important concepts for researchers to more fully understand the growth kinetics of ice crystals at the atomic scale.

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Yangrui Liu, Yun Li, Jing Wu, Xinyu Zhang, Pengfei Nan, Pengfei Wang, Dapeng Sun, Yumei Wang, Jinlong Zhu, Binghui Ge, Joseph S. Francisco. 2023-12-13. Direct visualization of molecular stacking in quasi-2D hexagonal ice. https://arxiv.org/abs/2312.08073

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