Optical spectroscopy on size selected gold clusters deposited in rare gas matrices

We report on the successful “soft-landing” of size selected Au trimers in solid Krypton matrices. The Au cations are produced by sputtering, mass-selected in a quadrupole mass spectrometer, co-deposited with Krypton on a cooled CaF₂ substrate, and neutralized by low energy electrons. The deposition of low kinetic energy cations (10 eV) gives rise to strong excitation bands, detected by the emitted fluorescence light, which are unambiguously attributed to Au trimers. The deposition and fragmentation process is qualitatively discussed.