贵金属纳米颗粒中从团簇到导体极限的静态屏蔽原子尺度结构
Atomic-scale structure of static screening in noble-metal nanoparticles from clusters to the conductor limit
查看机构详情
- Otto Schott Institute for Materials Research, Friedrich Schiller University（弗里德里希·席勒大学奥托·肖特材料研究所）
机构由 AI 辅助整理，请以论文原文为准。
浏览论文内容
中文总结 AI 辅助
本研究针对贵金属纳米颗粒，通过校准原子级电荷-偶极模型，揭示了静态屏蔽电荷的原子尺度结构，并实现了对超大体系的高效准确预测。
中文摘要 AI 辅助
金属纳米颗粒的静态屏蔽响应编码在其感应电荷密度中。诸如偶极矩或极化率等积分可观测量并不能确定该密度，因为许多不同的屏蔽分布可产生相同的积分。我们表明，在贵金属纳米颗粒中，屏蔽电荷具有原子级结构，其中面、边和顶点位点的响应与光滑的经典导体不同。即使当积分响应已达到导体极限时，这种结构仍存在于约一个原子宽度的表面层中，并且连续介质描述中缺失该结构。为了在不同尺寸、形貌和组分下解析该结构，我们直接将Ag和Au纳米颗粒的原子级电荷-偶极模型校准到第一性原理感应密度分布。校准包括纯静电模型忽略的硬度核的短程动能和交换关联贡献，将感应密度分布误差降低约2.5倍。每种元素的单一平均参数集可预测未参与拟合的团簇，并无需调整即可迁移至Ag/Au核壳、合金和拉长颗粒。该模型的连续快速多极实现几乎随原子数线性扩展，可处理数百万原子颗粒，远超第一性原理方法的适用范围。
英文摘要
The static screening response of a metallic nanoparticle is encoded in its induced charge density. Integrated observables such as the dipole moment or the polarizability do not determine this density, because many different screening profiles yield the same integrals. We show that in noble-metal nanoparticles the screening charge is atomically structured, with facet, edge, and vertex sites responding differently from a smooth classical conductor. This structure survives in a surface layer of about one atomic width even when the integrated response has reached the conductor limit, and it is absent from continuum descriptions. To resolve it across size, morphology, and composition, we calibrate an atomistic charge-dipole model for Ag and Au nanoparticles directly to first-principles induced-density profiles. The calibration includes the short-range kinetic and exchange-correlation contribution to the hardness kernel that a purely electrostatic model omits, reducing the induced-density-profile error by about a factor of 2.5. A single averaged parameter set per element predicts clusters withheld from the fit and transfers without adjustment to Ag/Au core-shell, alloyed, and elongated particles. A continuous fast multipole implementation of the model scales almost linearly with the number of atoms and reaches several-million-atom particles, far beyond the reach of first-principles methods.
