Gold dimer in neon: an absorption and fluorescence study

Abstract

Abstract. 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 2 P 1/2 → 2 D 3/2 , 2 P 1/2 → 2 D 5/2 and the 2 P 3/2 → 2 D 5/2 transitions. For the dimer, excitation of both A and B state results in distinct emission spectra with vibrational structure.

Intense fluorescence of Au20

“…25,33 For Au 2 , the fluorescence peak was at 809 nm (1.83 eV) and had a width of ∆E = 0.2 eV; 33 for Au 3 , there were three fluorescence peaks located at 529 nm (2.34 eV), 579 nm (2.14 eV), and 809 nm (1.53 eV). 25 Compared to the fluorescence reported for these small clusters, Au 20 has a fluorescence peak with significantly higher intensity.…”

UV–visible absorption of small gold clusters in neon: Aun (n = 1–5 and 7–9)

“…Comparison with previous measurements in neon 42 and in other matrices 43 confirms this spectrum except for the small secondary peak at 4.9 eV, which may be due to a less favorable second site isomer in the neon matrix. 39 The two large structures correspond to the spin-orbit split 2P 1/2 ← 2S 1/2 and 2P 3/2 ← 2S 1/2 transitions measured 44 respectively in gas phase at 4.63 and 5.11 eV. Au 2 .…”

“…The secondary peak at 3.13 eV has not been observed in other matrices. Fluorescence data 39 indicate that it is not due to a second site isomer. Comparison to gas phase measurements 47 suggests that it is related to the transition whose origin is situated at 2.98 eV.…”

“…The experimental absorption spectra of the atom and dimer in neon have already been discussed in a previous publication. 39 We present here these spectra for completeness together with the corresponding TD-DFT calculations.…”

“…Figure 2 presents the experimental spectra of small neutral gold clusters (Au n , n = 1-5 and 7-9) deposited in a neon matrix at 7 K. The atom and the dimer spectra have already been published together with their fluorescence spectra. 39 The hexamer has not been measured in this study because of its low abundance in the molecular beam. Figure 3 summarizes the experimental results and the TD-DFT spectra of the lowest energy Au isomers obtained in the calculation scheme described above.…”