Electron yields from clean polycrystalline metal surfaces by noble-gas-ion bombardment at energies around 1 keV

The total yield $\gamma$ of ion-induced electron emission has been measured for clean polycrystalline surfaces of 11 metals for normally incident ${\mathrm{Ar}}^{+}$ ions of 1.05 keV. For Ti and Cu the measurements have been extended to ${\mathrm{Kr}}^{+}$ and ${\mathrm{Xe}}^{+}$. The $\gamma$ values for the transition metals display a periodic variation with the atomic number of the target. The results are discussed on the basis of Hagstrum's theory and can be surprisingly well described by the interpolation formula of Kishinevsky derived from this theory. The applicability of this formula is discussed.