Oscillatory Ion Yields ofHe+Scattered from Atomic and Solid Pb Targets

Ion yields of ${\mathrm{He}}^{+}$ scattered from atomic and solid Pb in the energy range from 200 to 2000 eV into a large scattering angle are reported. The beam results show an oscillatory structure of the ion yield as function of the energy which is comparable to the same effects observed for a solid target. Thus the atomic nature of the quasiresonant charge exchange is confirmed. The data also give evidence for solid-state effects influencing the oscillations of the ion yield.