TOF-SIMS investigation of hydration of acetic acid adsorbed on amorphous water-ice surface

In order to gain insight into the acid-base reaction in the hydrogen bond systems, we have been investigating the hydration and ionization of the CH3COOH molecules adsorbed on the non-porous D2O-ice surface by time-of-flight secondary ion mass spectrometry. At temperatures above 60 K, the H+(CH3COOH) intensity (the H+(D2O) intensity) increases (decreases) due to the hydrogen-bond formation between the CH3COOH and D2O molecules. The D+(CH3COOD) ion evolves above 130 K as a result of the thermally induced proton transfer reactions between the CH3COOH and D2O molecules. The translational diffusion of the water molecules is responsible for the H/D exchange.