The adsorption and dehydrogenation of cyclopentane on Ru(001)

The adsorption of cyclopentane on Ru(001) has been studied using Electron Energy Loss Spectroscopy (EELS) and Thermal Desorption Mass Spectroscopy (TDMS). Thermal desorption shows with increasing coverage a chemisorbed first layer desorbing at 180 K with subsequent multilayer formation. The vibrational spectrum of the first chemisorbed layer is characterized by a C-H soft mode at 2610 cm^?1. This mode is ascribed to a C-H-metal interaction, which is also responsible for the dehydrogenation to cyclopentene upon annealing to 200 K. It appears that a $\text{close}$ geometrical fit between the $\text{entire}$ molecule and the metal substrate is not necessary for this type of interaction. Coadsorbed oxygen suppresses the C-H-metal interaction. This is believed to be due to site-blocking or ligand effects of oxygen on the three-fold hollow sites of Ru(001).