OPTICAL SPECTROSCOPY OF AG7, AG-9+, AND AG9 - A TEST OF THE PHOTODEPLETION METHOD

The optical absorption spectra of Ag7Kr, Ag9Kr, and Ag9Kr+ have been determined by photodepletion spectroscopy. The spectra are compared to previous spectra determined for silver clusters using two different experimental methods. Similar band shapes and band positions are found, validating the photodepletion technique. The observed spectra are sharper than previous ones due to the low temperature of our gas phase experiment. The measured integrated band strengths are smaller than previously found. These two observations are inconsistent with a description of the resonances as 'surface plasmon' excitations.