GIANT-RESONANCES IN PHOTON-EMISSION SPECTRA OF METAL-CLUSTERS

We consider radiative processes in collisions of electrons with metall ic clusters and demonstrate that the cluster giant resonance structure manifests itself in the photon emission spectrum. This effect occurs because the cross section of the process is mainly determined by the d ynamical polarizability of the cluster. We also demonstrate that the d iffraction of electrons at the cluster edge adds some peculiar oscilla tory structure to the cross section as a function of the photon freque ncy and as a function of the transferred momentum of the scattered ele ctron. The results are generalized for ion-cluster and cluster-cluster collisions.