Photodissociation of copper clusters, Cu +n ( n = 3–8), in the 370–710 nm wavelength region

Abstract

The photodissociation of copper clusters, Cu + n ( n = 3–8), has been investigated in the visible region of the spectrum (710-370 nm). Photodissociation spectra have been recorded, and information on the dissociation energies obtained from measurements of the laser fluence dependence of the photoproduct intensities. Accurate values for the dissociation energies of Cu + 6 (2.25 ± 0.10 eV) and Cu + 8 (2.375 ± 0.050 eV) have been determined from analysis of the lifetimes of photoexcited clusters using RRKM model. There are large oscillations in the dissociation energies. The even-numbered cluster ions are weakly bound and the odd-numbered ones strongly bound. For the neutral clusters, this behavior is reversed. A number of electronic trnsistions have been observed in the photodissociation spectra of the copper cluster ions. Qualitative assignments are proposed based on a correlation between the transistions observed in the atom, the clusters, and the bulk.