Direct Measurements of Surface Kinetics by Time-Resolved Electron Energy Loss Spectroscopy

The technique of time-resolved electron energy loss spectroscopy (TREELS) has progressed to the point where it is now appropriate to assess its present capabilities and future impact. In this article we will illustrate the way in which TREELS can contribute to our understanding of surface rate processes, specifically chemical kinetics“ As part of this assessment, it is useful to consider the basis for TREELS. In particular, we will highlight two key experimental developments, the incorporation of dispersion compensation and dispersive detection. These have resulted in greatly enhanced signal levels compared to conventional EELS (~102–103) and allowed the resolution of EELS measurements into small time units, of the order of 1 millisecond. With this result now experimentally confirmed, we will informally discuss selected traditional techniques used to obtain surface kinetic parameters and compare them to TREELS. A specific example of a surface rate process, the adsorption and desorption of CO from Cu(100), as studied by TREELS, is presented as a demonstration of present day capabilities.