HREELS studies of gold nanoparticles with dialkyl sulphide ligands

We have employed high resolution electron energy loss spectroscopy (HREELS) to study low energy electron impact on films of gold nanoparticles passivated with dialkyl sulphide (H21C10SC10H21). HREEL spectra obtained in UHV show energy loss peaks due to CHx and CC vibrational modes of the organic ligands together with a mode at 230 cm−1 assigned to the Au–S stretch. Measurements as a function of impact energy reveal resonances in the intensities centred between 9 and 12 eV. Prolonged exposure of the film to an electron beam at 50 eV, with a dosage of approximately 360 μC cm−2, causes significant changes in the HREEL spectra, consistent with cleavage of the Au–S bond.