Photochemical Reactivity of Gold Clusters: Dependence on Size and Spin Multiplicity

Noble metal clusters of sizes comparable to the Fermi wavelength are known to exhibit molecule-like transitions owing to the discretion of the density of states. In the present article, the important factors influencing the reactivity of excited gold (Au) clusters are examined from the viewpoint of molecular photochemistry. The investigation of the differently sized Au clusters embedded in a polymer film using single-molecule fluorescence spectroscopy facilitates the further understanding of their size-dependent photoreactivity. In addition, it was discovered that the spin multiplicity of the excited state (i.e., singlet or triplet excited state) governs the photoreactivity.