Adsorption and photodissociation dynamics of methyl iodide on magnesia supported gold nano-particles
Institute for Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
Corresponding author: a email@example.com
Published online: 6 March 2009
Methyl iodide represents a classical model for photodissociation and photoreaction of polyatomic molecules. Here, a new experimental approach is used to study the surface photoreaction dynamics of methyl iodide on magnesia and on magnesia supported gold particles employing pump-probe laser mass spectrometry. The adsorption of methyl iodide at submonolayer coverage on these substrates is investigated via temperature programmed desorption spectroscopy. Two distinct desorption peaks of molecular methyl iodide are identified corresponding to molecules bound to magnesia and more strongly bound to gold, respectively. This permits to selectively investigate the photoreaction of methyl iodide on the gold particles by choosing the appropriate temperature at which all molecules have been desorbed from MgO but not yet from the gold particles. The temperature dependent transient methyl fragment signal reveals the direct photoinduced dissociation dynamics on magnesia, whereas a quenching of the expected dissociation is observed on gold particles.
PACS: 68.47.Jn – Clusters on oxide surfaces / 82.53.Eb – Pump probe studies of photodissociation / 82.53.St – Femtochemistry of adsorbed molecules
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2009