Quantum state resolved molecular beam reflectivity measurements: CH4dissociation on Pt(111).
The King and Wells molecular beam reflectivity method has been used for a quantum state resolved study of the dissociative chemisorption of CH4on Pt(111) at several surface temperatures. Initial sticking coefficients S0were measured for incident CH4prepared both with a single quantum of ν3antisymmetric stretch vibration by infrared laser pumping and without laser excitation. Vibrational excitation of the ν3mode is observed to be less efficient than incident translational energy in promoting the dissociation reaction with a vibrational efficacy ην3= 0.65. The initial state resolved sticking coefficient S0ν3was found to be independent of the surface temperature over the 50 kJ/mol to 120 kJ/mol translational energy range studied here. However, the surface temperature dependence of the King and Wells data reveals the migration of adsorbed carbon formed by CH4dissociation on the Pt(111) surface leading to the growth of carbon particles.
Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
Helen
H
Chadwick
Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
Ana
A
Gutiérrez-González
Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
Rainer D
RD
Beck