School of Physics & Optoelectronic Technology, School of Chemical Engineering and College of Advanced Science and Technology, Dalian University of Technology, Dalian 116024, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2010 Feb;75(2):794-8. doi: 10.1016/j.saa.2009.11.057. Epub 2009 Dec 3.
The chemical mechanism of Normal Raman Scattering (NRS) and pre-surface enhanced Raman scattering (pre-SERS) spectra for Pyrazine-Ag(2) complex, Ag(2)-Pyrazine-Ag(2) junction and Ag(2)-Pyrazine-Au(2) junction were investigated with density functional theory (DFT) and charge difference densities (CDDs) for the first time. The NRS intensities of the above three structures enhanced obviously relative to isolated Pyrazine and the enhancement mechanism was confirmed to be static chemical enhancement. The pre-SERS intensities of the above three structures enhanced evidently compared to corresponding NRS intensities, and the enhancement mechanism was confirmed to charge transfer (CT) resonance Raman enhancement. The largest enhanced orders of NRS and pre-SERS intensities among the three structures were up to 10(3) and 10(5), respectively. Compared the intensity of pre-SERS with corresponding intensity of NRS spectra, the enhancement effect of Pyrazine-Ag(2) complex was larger than the others. Intramolecular and intermolecular CT on resonant electronic transition were described by CDDs.
首次运用密度泛函理论（DFT）和电荷差分密度（CDD）研究了吡嗪-Ag（2）配合物、Ag（2）-吡嗪-Ag（2）结和 Ag（2）-吡嗪-Au（2）结的 Normal Raman Scattering（NRS）和预表面增强 Raman 散射（pre-SERS）光谱的化学机制。与孤立的吡嗪相比，上述三种结构的 NRS 强度明显增强，增强机制被确认为静态化学增强。与相应的 NRS 强度相比，上述三种结构的 pre-SERS 强度明显增强，增强机制被确认为电荷转移（CT）共振拉曼增强。三种结构中 NRS 和 pre-SERS 强度的最大增强阶数分别高达 10（3）和 10（5）。与相应的 NRS 谱强度相比，吡嗪-Ag（2）配合物的增强效果大于其他两种。通过 CDD 描述了共振电子跃迁上的分子内和分子间 CT。
