| AVS 54th International Symposium | |
| Surface Science | Monday Sessions |
| Session SS1-MoA |
| Session: | Water-Surface Interactions |
| Presenter: | T. Kondo, RIKEN and University of Tsukuba, Japan |
| Authors: | T. Kondo, RIKEN and University of Tsukuba, Japan H.S. Kato, RIKEN, Japan M. Bonn, AMOLF, FOM, The Netherlands M. Kawai, RIKEN and University of Tokyo, Japan |
| Correspondent: | Click to Email |
The deposition and the isothermal crystallization kinetics of thin amorphous solid water (ASW) films on both Ru(0001) and CO-precovered Ru(0001) have been investigated in real time by simultaneously employing helium atom scattering, infrared reflection absorption spectroscopy and isothermal temperature-programmed desorption. The modification of the Ru(0001) surface by the pre-adsorption of CO has been found to affect the deposition feature of water layers at the water coverage below ~5 ML: whereas an ordered first layer structure of water is formed on both the bare surface and the surface pre-adsorbed with 0.33 ML CO, a disordered structure is formed when 0.65 ML CO is pre-adsorbed. During ASW deposition, the interaction between water and the substrate depends critically on the amount of pre-adsorbed CO. However, the mechanism and kinetics of the crystallization of ~50 layers thick ASW film were found to be independent of the amount of pre-adsorbed CO. We demonstrate that crystallization occurs through random nucleation events in the bulk of the material, followed by homogeneous growth, for solid water on both substrates with an apparent activation energy of 650 ± 25 meV. The morphological change accompanying the formation of 3D grains of crystalline ice results in the exposure of the water monolayer just above the substrate to the vacuum. Remarkably enough, the appearance of this first water layer occurs already during the crystallization process, on both substrates.