[en] The secondary electron emission due to impact of a variety of atomic, molecular and cluster ions on pure and contaminated gold surfaces was investigated with an ion-electron converter. The measured frequency distribution of the electron groups released in a single impact process was compared with a Polya distribution, from which the mean secondary electron yield was determined. The velocity dependence of the SE yield from pure gold surfaces shows marked deviations from theoretical predictions. The results with contaminated surfaces are comparable with the SE emission from insulators. The SE yield of one particle in a cluster ion or molecular ion is equal to the yield of an atomic ion of the same velocity. There are no nonlinear effects as in the emission of atoms in sputtering. The dependence of the SE yield on the atomic number Z₁ of the projectile ion shows continuous variation of the SE yield ranging over one order of magnitude, and so it is much stronger than for contaminated surfaces. Superposed on this Z₁ oszillation is a fine structure in keeping with the step by step filling of the electron shells in the periodic system. (orig.)