Ethane dissociation dynamics on Pt(111)

Abstract

Supersonic molecular beam techniques were used to measure the initial dissociative sticking probability, S 0, of ethane on clean Pt(111) as a function of its translational energy, vibrational energy in excited states, incident angle with respect to the surface normal and surface temperature. At incident total translational energies greater than 81 kJ/mol, ethane dissociates on Pt(111) via direct collisional activation. Over the range of energies studied the initial dissociative sticking probability on the clean surface increases smoothly with increasing normal translational energy. Neither changes in the vibrational energy of the incident ethane nor the surface temperature affect ethane dissociation on Pt(111) within the limits of experimental error. The initial dissociative sticking probabilities for the direct collisional activation of methane and ethane on Pt(111) are nearly equal over a similar range of translational energies suggesting that the initial step for ethane dissociation involves C|H bond cleavage.