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 hive been determined over the wavelength range 260 - 740 nm by photodetaching Krypton atoms from the corresponding neutral van der Waals, vdW, complexes, Nb(n)Kr(m), n=5-15, m=1-3. Cross sections for small gold clusters were determined by photodetachment experiments on charged vdW complexes [Au(n)Xe(m)]+, 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.