Interpreting the chemical mechanism in SERS using a Raman bond model
Interpreting the chemical mechanism in SERS using a Raman bond model
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DOI：
10.1063/1.5138204
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发表时间：
2020-01-14
影响因子：
4.4
通讯作者：
Jensen, Lasse
中科院分区：
文献类型：
--
作者：
Chen, Ran;Jensen, Lasse
我们提出了一个第一性原理模型，分区拉曼强度的原子和债券的贡献。这个框架使我们能够解释的化学机制，在表面增强拉曼散射（Sers）作为原子间的电荷流调制，我们定义为拉曼键。Hirshfeld分区和电荷密度本地化表示的极化率衍生物的电荷流调制。用含时密度泛函理论研究了吡啶、硫醇和卡宾与金属团簇相互作用的模型体系。我们证明，特定模式的增强可以解释为拉曼键共轭跨越分子-金属界面。我们还说明，由电场或化学取代引起的拉曼强度的变化通常可以解释为电荷流的变化。该模型被证明是一致的工作为不同类型的分子-金属键。此外，我们的工作表明，增加跨界面的拉曼键共轭导致更强的化学增强。本文提出的拉曼键模型对Sers中的化学机制提供了一个定量和直观的解释。
We present a first-principles model that partitions Raman intensities to atomic and bond contributions. This framework allows us to interpret the chemical mechanism in surface-enhanced Raman scattering (SERS) as interatom charge flow modulations, which we define as Raman bonds. Hirshfeld partitioning and charge density localization are applied to express polarizability derivatives as charge flow modulations. Model systems consisting of pyridines, thiols, and carbenes interacting with metal clusters are studied using time-dependent density functional theory. We demonstrate that the mode-specific enhancements can be explained as Raman bonds conjugated across the molecule-metal interface. We also illustrate that the changes in Raman intensities induced by electric fields or chemical substitutions can generally be interpreted as changes of charge flows. The model is shown to work consistently for different types of molecule-metal bonds. Furthermore, our work shows that increasing the Raman bond conjugation across the interface leads to stronger chemical enhancements. The Raman bond model developed in this work provides a quantitative and intuitive interpretation of the chemical mechanism in SERS.