A MULTIMETHOD-INVESTIGATION OF THE ADSORPTION OF ETHYLENE-OXIDE ON NI(110)

The adsorption of ethylene oxide on Ni(110) has been studied by TPD, w ork function measurements, LEED, XPS, and angle resolved UPS using lin early polarized synchrotron radiation. At temperatures below 100 K eth ylene oxide adsorbs in molecular form on Ni(110) with a saturation cov erage of approximately 0.5 ML (1 ML = 1 molecule/Ni atom). Upon heatin g, molecular desorption occurs in a broad peak ranging from approximat ely 110 to 240 K; there is no indication of dissociation, as concluded from TPD and XPS. At saturation a sharp c(2 x 2) LEED pattern is obse rved. From ARUPS we deduce that the C2 rotation axis of the molecule i s tilted away from the surface normal and that the mirror planes of th e molecule do not coincide with the substrate mirror planes, independe nt of coverage.