2000 Volume 43 Issue 7 Pages 745-749
At various surface temperatures (400, 600 and 800 K), after irradiation of a hyperthermal CH4 molecular beam as much as 25000 L, the work function of the Pt (111) surface was measured by a Kelvin probe to find a relationship between the work function and the reaction products.
It was found by HAS (Helium Atom Scattering), AES/LEED and work function measurements that a monolayer of the reaction products (ethylidyne, hydrocarbon and graphite) form only at the beam irradiated area. The species and the amount of these products depend on the surface temperature; a large amount of graphite at 800 K, a medium amount of hydrocarbon at 600 K and a small amount of ethylidyne at 400 K. The work function of the Pt (111) surface covered by graphite decreases as much as 0.8 eV from that of a clean Pt (111) surface. The work function of the Pt (111) surface covered by ethylidyne is nearly the same as that of hydrocarbon covered surface in spite of their difference in surface coverage. This seems to be attributed to the formation of the dipole caused by the charge transfer from, ethylidyne to Pt (111) surface.
