Contributions of r−1, r−2, r−3 terms of the full dipole fields associated with Raman scattering enhancement from CN molecules adsorbed on a 2-D array of Ag spheroids

Abstract

The enhancement of Raman scattering from a CN molecule adsorbed on the tip of one of a 2-D array of Ag spheroids has been newly calculated using the full dipole fields. Results are compared to the corresponding experimental data from the lithographically produced Ag microspheroids. While the r−1 term is small in our specific configuration of molecule-spheroids arrangement, the r−2 term of the full dipole fields is found to contribute about the same amount to the excitation profile of the Raman enhancement as the conventional r−3 term. We also find a kind of spectral fluctuation in the Raman excitation profile and have demonstrated it as due to the interference between the r−2 and r−3 fields.

Ag-Clad Au Nanoparticles: Novel Aggregation, Optical, and Surface-Enhanced Raman Scattering Properties

“…Although these data are noisier than those obtained at higher concentrations, it appears that the degree of aggregation is again roughly the same for all BPE solutions. Considering theoretical investigations of closely spaced colloidal particles, − , it is likely that these small absorbance changes derive from the creation of dimers, trimers, or similar low-nuclearity structures. In accord with these findings, we have shown that, in aggregates derived from 20 nm diameter Au, removal of all particle clusters with effective diameters greater than 100 nm eliminates only 90−95% of the SERS activity…”