Atomic Cluster Au10+ Is a Strong Broadband Midinfrared Chromophore

We report an intense broadband midinfrared absorption band in the Au-10(+) cluster in a region in which only molecular vibrations would normally be expected. Observed in the infrared multiple photon dissociation spectra of Au10Ar+, Au-10(N2O)(+), and Au-10(OCS)(+), the smooth feature stretches 700- 3400 cm(-1) (lambda = 14-2.9 mu m). Calculations confirm unusually low-energy allowed electronic excitations consistent with the observed spectra. In Au-10(OCS)(+), IR absorption throughout the band drives OCS decomposition resulting in CO loss, providing an alternative method of bond activation or breaking.

Automated summary

An intense broadband midinfrared absorption band was reported in the Au-10(+) cluster, where only molecular vibrations would normally be expected. The observed smooth feature stretches from 700 to 3400 cm(-1) (lambda = 14-2.9 μm) in infrared multiple photon dissociation spectra. The calculations confirmed unusually low-energy allowed electronic excitations consistent with the observed spectra.