Contribution of broadening effects to chemisorptive emission

The effects of energy broadening on the spontaneous emission of electrons during chemisorption (“chemisorptive emission”) are considered using an approach formerly used with success by Hagstrum for the related process of ion neutralization. Broadening is assumed to arise from two sources: electron tunnelling occurs over a range of distances from the surface, and the lifetime of the initial state is finite. Experimentally determined electron yields for electronegative gases adsorbing on highly electropositive metals are used to determine appropriate broadening parameters, which generally agree well with resonance widths used by other authors for similar systems.