The adsorption of ethylene on ethylidyne-covered Pd(111)

Reflection absorption infrared spectroscopy shows that ethylene adsorbs on ethylidyne-saturated Pd(1 1 1) ðHsatðCH3–CBÞ 1⁄4 0:25Þ at 80 K exhibiting a feature at 1100 cm , assigned to di-r-bonded ethylene adsorbed on the palladium surface. Since adsorbed ethylidyne also has a vibrational mode at 1090 cm , the assignment of the 1100 cm 1 mode to adsorbed ethylene was confirmed by adsorbing it on an ethylidyne-covered surface grown using deuterated ethylene. The adsorption of ethylene on ethylidyne-covered Pd(1 1 1) was further confirmed using temperatureprogrammed desorption which revealed that the saturation ethylene coverage on ethylidyne-covered Pd(1 1 1) is 0.25 compared to 0.33 for ethylene on clean Pd(1 1 1). 2002 Elsevier Science B.V. All rights reserved.