Electron-stimulated desorption of europium atoms from the surface of a germanium monolayer deposited on tungsten

The adsorption of europium on the surface of a germanium monolayer deposited on a tungsten substrate using electron-stimulated desorption was studied. It was found that the electron-stimulated desorption of Eu atoms at europium coverages of less than 0.3 monolayers is caused by the excitation of the Eu $5p$ and Eu $5s$ states, and at coverages of more than 0.4 monolayers it is caused by the excitation of the states: W $4f$, W $5p$ and W $5s$. A model of electronic transitions has been proposed to explain the processes that occur during the electron-stimulated desorption of europium atoms.