The adsorption of Xe and CO on Ag(111)

The adsorption of Xe and CO on Ag(111) in the range 66 to 123 K and 10^?7 to 10^?1 Pa has been studied by surface potential, low energy electron diffraction (LEED), Auger electron spectroscopy (AES) and electron energy loss spectroscopic (EELS) measurements. Isotherms derived from both surface potential and AES measurements for submonolayer Xe adsorption reveal successive stages and a two-dimensional phase change. Isosteric heats were 18 ± 1 kJ mol^?1. Temkin isotherms were observed for CO, the heat falling linearly with coverage from an initial value of 27 ± 1.5 kj mol^?1. No ordered CO overlayer structure could be detected. EEL spectra of clean Ag(111) agree with previous studies. Additional loss peaks were recorded for Xe and CO overlayers, and the assignment of the substrate loss features is discussed in relation to the effects of adsorption.