Absorption cross-section spectroscopy of a single strong-coupling system between plasmon and molecular exciton resonance using a single silver nanoparticle dimer generating surface-enhanced resonant Raman scattering

摘要

This study investigates spectral changes in the absorption cross sections of single strong coupling systems composed of single silver nanoparticle dimers and a few dye molecules during the quenching of surface-enhanced resonant Raman scattering (SERRS). The absorption cross section is obtained by subtracting the scattering cross section from an extinction cross section. The spectral changes in these cross sections are evaluated using a classical hybridization model composed of a plasmon and a molecular exciton including a molecular multilevel property. The changes in the scattering and extinction cross sections exhibit blueshifts in peak energy and increases in peak intensities, respectively, during SERRS quenching. These properties are effectively reproduced in the model by decreasing the coupling energy. In particular, the peaks in the scattering and extinction cross sections appear as peaks or dip-like structures in the absorption cross sections depending on the degree of scattering loss, which reflects the dimer sizes. These results are useful for optimizing photophysical and photochemical effects mediated by the electronic excited states of strong coupling systems.