TY  - JOUR
A1  - Heiden, Sophia
A1  - Wirth, Jonas
A1  - Campen, Richard Kramer
A1  - Saalfrank, Peter
T1  - Water molecular beam scattering at alpha-Al2O3(0001)
T2  - The journal of physical chemistry : C, Nanomaterials and interfaces
N2  - Recent molecular beam experiments have shown that water may adsorb molecularly or dissociatively on an α-Al2O3(0001) surface, with enhanced dissociation probability compared to “pinhole dosing”, i.e., adsorption under thermal equilibrium conditions. However, precise information on the ongoing reactions and their relative probabilities is missing. In order to shed light on molecular beam scattering for this system, we perform ab initio molecular dynamics calculations to simulate water colliding with α-Al2O3(0001). We find that single water molecules hitting a cold, clean surface from the gas phase are either reflected, molecularly adsorbed, or dissociated (so-called 1–2 dissociation only). A certain minimum translational energy (above 0.1 eV) seems to be required to enforce dissociation, which may explain the higher dissociation probability in molecular beam experiments. When the surface is heated and/or when refined surface and beam models are applied (preadsorption with water or water fragments, clustering and internal preexcitation in the beam), additional channels open, among them physisorption, water clustering on the surface, and so-called 1–4 and 1–4′ dissociation.
Y1  - 2018
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/52472
SN  - 1932-7447
VL  - 122
IS  - 27
SP  - 15494
EP  - 15504
PB  - American Chemical Society
CY  - Washington
ER  -