Title: Observing ice structure of micron-sized vapor-deposited ice with an X-ray Free-electron Laser
Author: Seonmyeong Kim, Matlabjon Sattorov, Dongpyo Hong, Heon Kang, Jaehun Park, Jae Hyuk Lee, Rory Ma, Andrew V Martin, Carl Caleman, Jonas A Sellberg, Prasanta Kumar Datta, Sang Yoon Park, and Gun-Sik Park
The direct observation of the structure of micron-sized vapor-deposited ice is performed at Pohang Accel- erator Laboratory X-ray Free Electron Laser (PAL-XFEL). The formation of micron-sized ice crystals and their structure is important in various fields, including atmospheric science, cryobiology, and astrophysics, but understanding the structure of micron-sized ice crystals remains challenging due to the lack of direct observation. Using intense X-ray diffraction from PAL-XFEL, we could observe the structure of micron-sized vapor-deposited ice below 150 K with a thickness of 2 - 50 µm grown in an ultrahigh vacuum chamber. The structure of the ice grown comprises cubic and hexagonal sequences that are randomly arranged to produce a stacking-disordered ice. We observed that ice with a high cubicity of more than 80% was transformed to partially oriented hexagonal ice when the thickness of the ice deposition grew beyond 5 µm. This suggests that precise temperature control and clean deposition conditions allow µm-thick ice films with high cubicity to be grown on hydrophilic Si3N4 membranes. The low influence of impurities could enable in-situ diffraction experiments of ice nucleation and growth from interfacial layers to bulk ice.
논문지: Structural Dynamics