Simulating Ensemble-Averaged Surface-Enhanced Raman\nScattering

Abstract

The ability to simulate\nsurface-enhanced Raman scattering (SERS)\nis a vital tool in elucidating the chemistry of molecules near the\nvicinity of plasmonic metal nanoparticles. However, typical methods\ndo not include the dynamics of the molecule(s) of interest and are\noften limited to a single or few molecules. In this work, we combine\nmolecular dynamics simulations with the dressed-tensor formalism to\nsimulate the SERS spectra of Ag nanoparticles coated with a full monolayer\nof pyridine molecules. This method allows us to simulate the ensemble-averaged\nSERS spectra of more realistic large scale systems, while accounting\nfor the organization of molecules in the hotspots. Through these simulations,\nwe find that the preferential binding location and orientation of\nthe molecules, the choice of electrodynamics method, and the inclusion\nof field gradient effects influence both the enhancement distribution\nand the spectral signatures. We also show that both the translational\nand rotational motions of a pyridine molecule near a nanoparticle\njunction may be effectively tracked through its SERS spectrum.