Speaker
Description
Light-driven charge transfer at metal–molecule interfaces depends on nonequilibrium electron dynamics in the nanoparticle and on the contact electronic structure. We present a model for a sulfur-linked molecule on a gold nanoparticle dimer, treating the nanoparticle as a geometry-aware metallic electron system and the local Au–S–molecule region as a finite metal–molecule contact. A Maxwell–electron-hydrodynamic response gives the optical field, induced current, and density perturbation; these quantities drive a kinetic description of Fermi–Dirac and nonthermal electron populations, using plasmonic electron-generation models and energy-dependent e–e/e–ph scattering rates [1,3].
Interfacial fractional charge transfer is formulated by perturbing the coupling term in the reduced-density-matrix equation of motion [1,2]. The density perturbation and kinetic electron distribution estimate a fractional excess electron number $\eta$, defining an $N+\eta$ contact reference. The contact is treated as a density functional tight-binding (DFTB) subsystem coupled perturbatively to the nanoparticle-scale electron source. Linear-response time-dependent DFTB around this reference provides transition densities, orbital participation, and fragment charge redistribution across the Au–S–molecule interface [4].
The model determines how geometry-dependent nonequilibrium electron kinetics produces fractional interfacial charge transfer and molecular charge redistribution. It resolves charge-transfer channels by electron energy, hotspot localization, dimer geometry, and metal–molecule hybridization, and evaluates consistency with XPS binding-energy, valence-band, and work-function constraints [5].