Electron and Ion Emission from Iridium in Lithium Vapor

Abstract

The electron and ion emissioncharacteristics of the adsorption system lithium on iridium are reported in the range of lithium arrival flux from 1013 to 1018 atoms/cm2·sec. The electron emissionS curves exhibit a 2.80‐eV heavily lithium‐covered work function, no minimum in the composite work function, a 5.35‐eV bare iridiumwork function, and a stronger dependence on lithium flux than for cesium. The surface ionization of lithium on iridium exhibits ionization efficiencies from 10%–35% and a critical temperature envelope, the slope of which yields 2.10 eV for the desorption energy of lithium ions from iridium at critical coverage.