Gold dimer in neon: an absorption and fluorescence study

We report for the first time the absorption and fluorescence spectra of gold dimers in a neon matrix. The dimer absorption spectra show the A←X transition predicted from measurements in the gas phase and not observed so far in a matrix, as well as the so-called B←X and C←X transitions. Fluorescence measurements on the atom reveal new emission lines at 1.97, 3.59 and 4.09 eV that can be assigned to the 2P1/2→2D3/2, 2P1/2→2D5/2 and the 2P3/2→2D5/2 transitions. For the dimer, excitation of both A and B state results in distinct emission spectra with vibrational structure.