Presentation Information
[3E10]Orientational Dynamics of Two–Dimensional Ice on Pt(111) under the Influence of Dimensional Crossover to Three–Dimensional Hydrogen–Bond Networks
*Yuta Takahara1,2, Shota Takahashi2, Tsuneto Kanai2, Atsunori Sakurai1,2, Toshiki Sugimoto1,2 (1. Graduate Institute for Advanced Studies, SOKENDAI, 2. Institute for Molecular Science)
We investigated the orientational dynamics of two–dimensional (2D) ice on Pt(111) substrate, where strong substrate–induced pinning creates highly ordered crystalline ice films. While this pinning governs macroscopic orientational stability, how it responds to the formation of three-dimensional (3D) hydrogen–bond (H–bond) networks remained unclear. By developing a high–sensitivity, rapid–acquisition phase–sensitive vibrational sum–frequency generation (PS–VSFG) spectroscopy system, combined with temperature–programmed desorption, we directly tracked the thermal disordering of proton–ordered 2D ice. The results reveal a second–order–like orientational transition at around 161 K. Notably, the growth of 3D ice on the 2D layer destabilized the orientational order of the buried 2D layer, likely due to bidirectional cooperative coupling that transmits enhanced fluctuations from the 3D overlayer. These findings provide molecular–level insight into the interplay across dimensional H–bond networks and highlight PS–VSFG as a powerful probe of orientational dynamics in low–dimensional H–bonded systems.