PHOTOIONIZATION OF ALKALI-METAL CLUSTERS

The photoionization cross section for spherical alkali metal clusters is predicted to oscillate as a function of the photon wavenumber with a frequency determined by the diameter of the cluster. The oscillation s and other principal features of the photo cross section can be worke d out analytically using semiclassical techniques. An accurate numeric al calculation with different cluster potentials confirms these result s qualitatively. Quantitative details depend sensitively on the actual potential. Hence, properties of the true cluster potential can be inf erred from the experimental cross section. This might turn out to be u seful for improving theoretical cluster potentials.