Absorption spectra of small niobium and gold clusters measured by photodepletion of their rare gas van der Waals complexes: some preliminary experiments

The optical absorption spectra of small niobium clusters have been determined over the wavelength range 260 – 740 nm by photodetaching Krypton atoms from the corresponding neutral van der Waals, vdW, complexes, NbnKrm, n=5–15, m=1–3. Cross sections for small gold clusters were determined by photodetachment experiments oncharged vdW complexes [AunXem]+, m=1, 2. The absorption cross sections are observed to increase monotonically with decreasing wavelength. At the long wavelength end of the range, the cross section is practically independent of the cluster nuclearity, n; whereas, at the short wavelength end of the range, the cross section increases monotonically with n.