Optical properties of size selected neutral Ag clusters: electronic shell structures and the surface plasmon resonance

Abstract

We present optical absorption spectra from the ultraviolet to the visible for size selected neutral Agn clusters (n = 5–120) embedded in solid Ne.

Localized Surface Plasmon Resonance in Free Silver Nanoclusters Agn, n = 20–147

“…The calculated absorption spectra of Ag 92 , Ag 58 and Ag + 55 are compared to most recent experimental spectra. 23 As expected, only the range-separated hybrid ωB97x is able to reproduce the experimental data. Indeed, TDDFT calculations with a local exchange and correlation potential in the adiabatic approximation can not correctly describe the interband d → sp transitions since the latter present Rydberg and long-range charge-transfer characters that can only be described with a RSH-type density functional.…”

“…A secondary band centered at 4.56 eV is also calculated, but not see in experiments. 23 Interestingly both bands were calculated at 4.23 and 4.66 eV respectively for the cation Ag + 55 (Fig. 1).…”

“…Then they are likely to be lost 2 in the interbands (transitions associated to d-electrons) or in the bands resulting from hybridization with protecting ligands bound to the surface of clusters. 20,21 But silver is a exception since the plasmon-like band is clearly visible down to small size bare clusters of about 18-20 atoms 22,23 thanks to a relatively strong alkali-like character with a large s-d separation. 24 Absorption spectra of medium-sized and small-sized silver clusters have been measured in vacuum, 25 in solution, 26 in solid rare-gas matrices, 22,[27][28][29] and in supported samples on glass.…”

Spectroscopy for model heterogeneous asymmetric catalysis

“…Scientists have come up with various clever workarounds to this problem, which are, however, not appropriate when considering model HeACs. In one approach, the clusters are codeposited with rare gas atoms on a cryogenically cooled surface and thus are embedded in a solid rare gas matrix . This way, the sample is not limited to one surface layer and is extended in the third dimension, and thus, a larger number of particles can be investigated without the risk of interparticle interactions.…”

“…In one approach, the clusters are codeposited with rare gas atoms on a cryogenically cooled surface and thus are embedded in a solid rare gas matrix. 119,120 This way, the sample is not limited to one surface layer and is extended in the third dimension, and thus, a larger number of particles can be investigated without the risk of interparticle interactions. Thus, the signal intensity is enhanced, and common optical absorption techniques might be suitable for the analysis.…”