CN DESORPTION FROM POTASSIUM-METAL SURFACES UNDER ELECTRON-BOMBARDMENT

First measurements of the energy-dependent desorption cross sections near threshold energy for electron-stimulated desorption of excited CN molecules from potassium-metal surfaces are presented. Threshold energies were observed to be different when the alkali metal surface was exposed to a CO2 + N-2 mixture from that when exposed to H-2 gas, leading to the conclusion that two different chemical processes are involved. The rotational energy distribution was observed to be independent of incident electron energy. We postulate a desorption model similar to the Antoniewicz model.