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

Abstract

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 CH 3COOH molecules adsorbed on the non-porous D 2O-ice surface by time-of-flight secondary ion mass spectrometry. At temperatures above 60 K, the H +(CH 3COOH) intensity (the H +(D 2O) intensity) increases (decreases) due to the hydrogen-bond formation between the CH 3COOH and D 2O molecules. The D +(CH 3COOD) ion evolves above 130 K as a result of the thermally induced proton transfer reactions between the CH 3COOH and D 2O molecules. The translational diffusion of the water molecules is responsible for the H/D exchange.