Optical extinction on free, supported and embedded metal clusters

To study changes of the optical properties of clusters due to interactions with matrices and substrates, clusters of several nm diameter were produced by the inert gas condensation and by the gas free expansion technique. Theoretical predictions for the cluster formation process could be verified. Optical extinction was measured on the free cluster beam, after deposition on quartz substrates and after embedding in quartz matrices. Several of the samples were analyzed by TEM. It is shown, that at high source temperatureT0 the free clusters remain liquid on their way through the vacuum chamber but solidify there ifT0 is decreased. At higherT0 oblate ellipsoids are formed during the deposition. The spectra of the free beam deviate from theoretical predictions.