Direct measurement of kinetic data by time-resolved high-resolution electron-energy-loss spectroscopy

High-resolution (ΔE<10 meV) electron-energy-loss spectroscopy (EELS) was used to measure directly (in real time) isothermal adsorption and desorption parameters of CO on Ni(111) at temperatures above 110?deC by monitoring the EELS intensity response on gas pulses produced by a chopped nozzle beam. For coverages of ${10}^{\mathrm{-}3}$<CTHETA≤0.2 a constant desorption energy of 108 kJ/mol and a constant preexponential factor of 3×${10}^{+12\mathrm{}}$ ${\sec }^{\mathrm{-}1}$ is found. Independently of coverage and temperature, the ratio of the relative intensities of the stretching modes of CO molecules occupying on-top and bridge positions is around (1/3).