It is shown that Gibbsian segregation is an important feature of the redistribution of alkali metal in the surface of glass during electron irradiation. A model that couples the effects of segregation, desorption, and diffusion is presented. The model is used to simulate the alkali-metal ion desorption flux, and both the ion-scattering- and Auger-electron-spectroscopy signal changes, which have been experimentally measured.

• Received 28 September 1990

DOI:https://doi.org/10.1103/PhysRevB.43.3831