Atomistic Multiscale Modeling of Colloidal Plasmonic Nanoparticles

TL;DR

This paper introduces a new atomistic multiscale classical modeling approach for accurately simulating the optical response of solvated plasmonic nanoparticles, capturing interactions with the environment and validating against quantum calculations.

Contribution

The novel $ ext{ω}$FQF$ ext{μ}$/FQ model combines plasmonic and solvent interactions at the atomistic level, offering high accuracy for nanoparticle optical properties.

Findings

Accurately reproduces plasmon resonance shifts for small structures.

Validates against TD-DFTB/FQ calculations with remarkable accuracy.

Successfully simulates optical responses of various nanoparticle systems.

Abstract

A novel fully atomistic multiscale classical approach to model the optical response of solvated real-size plasmonic nanoparticles (NPs) is presented. The model is based on the coupling of the Frequency Dependent Fluctuating Charges and Fluctuating Dipoles ($\omega$FQF$\mu$), specifically designed to describe plasmonic substrates, and the polarizable Fluctuating Charges (FQ) classical force field to model the solvating environment. The resulting $\omega$FQF$\mu$/FQ approach accounts for the interactions between the radiation and the NP, as well as with the surrounding solvent molecules, by incorporating mutual interactions between the plasmonic substrate and solvent. $\omega$FQF$\mu$/FQ is validated against reference TD-DFTB/FQ calculations, demonstrating remarkable accuracy, particularly in reproducing plasmon resonance frequency shifts for structures below the quantum-size limit. The flexibility and reliability of the approach are also demonstrated by simulating the optical response of homogeneous and bimetallic NPs dissolved in pure solvents and solvent mixtures.