Understanding chemical effects on the plasmonic properties of a metal nanomaterial due to the surface molecules on that metal is of great importance in the field of plasmonics and these effects have yet to be completely elucidated. Here, we report mechanisms of the chemically induced change in the electronic state at the metal-ligand interface of silver nanoparticles due to the ligand molecules, and the effect of this change on the plasmonic properties of those nanoparticles. It was found that changes in the electron density of states at the metal-ligand interface cause alterations in the induced and permanent dipole moments, and eventually to the permittivity at the interface, when the wave function near the Fermi level is localized at the interface. These alterations play a key role in determining the plasmonic properties of silver nanoparticles. The present findings provide a more precise understanding of the interconnection between the electronic states at the metal-organic interface and the plasmonic properties of the metal.

了解由于金属表面分子对金属纳米材料的等离子体性质的化学影响在等离子体领域非常重要，这些影响尚未完全阐明。在这里，我们报告了由于配体分子在银纳米粒子的金属-配体界面处化学诱导的电子态变化的机制，以及这种变化对这些纳米粒子的等离子体性质的影响。研究发现，当费米能级附近的波函数位于界面处时，金属-配体界面的电子态密度变化会导致感应偶极矩和永久偶极矩发生变化，并最终导致界面处的介电常数发生变化。这些改变在确定银纳米粒子的等离子体特性中起着关键作用。