LI-MODIFIED OSCILLATIONS IN CO OXIDATION ON A PT FIELD EMITTER

The first observations of Li-modified isothermal kinetic oscillations during CO oxidation on a Pt field emitter tip are reported. The oscill ations are realized on the surface of a [111]-oriented Pt tip in the p resence of a Li submonolayer coverage of about 2.5 x 10(14) cm(-2) and are compared to the corresponding Li-free oscillations occurring on t he same tip. In both cases the oscillatory process is visualized using the field electron emission (FEM) mode of the lithium field desorptio n microscope (Li-FDM). The origin of the FEM imaging contrast of coads orbed Li-CO and Li-O layers on Pt is clarified. The influence of the c oadsorbed Li submonolayer on the oscillating behavior of CO oxidation on Pt is discussed.