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文中从实验和计算两方面报道了在514.5 nm激发光下p-Thiocresol吸附在银胶表面系统的表面增强拉曼散射(SERS).文中分析了它的增强机制,发现增强主要来自于电磁场增强.如果考虑距离为2 nm的两个银纳米粒子的耦合效应,两粒子之间的SERS的电磁场增强为7.16×107.静态化学增强亦起到部分增强作用,它的增强倍数为6.所以,总的SERS增强,包括静态化学增强和电磁场增强,是Gtotal=GSC×GEM=4.4×108.我们也理论地研究了此系统的表面增强共振拉曼散射(SERRS).当激发光与p-Thiocre-sol-Ag3系统的激发态共振时,电荷转移机制(化学增强)也将起到重要作用,最强的增强可达106.我们使用电荷密度将激发光下p-Thiocresol和Ag团簇间的电荷转移结果可视化,这是电荷转移的直接理论证据.对于SERRS增强,包括电荷转移和电磁场增强机制,能达到1013.
In this paper, the surface enhanced Raman scattering (SERS) of p-Thiocresol adsorbed on the surface of silver colloids was reported experimentally and computationally. The enhancement mechanism of p-Thiocresol adsorbed on the silver colloidal surface was reported. The enhancement was mainly attributed to the enhancement of electromagnetic field. If we consider the coupling effect of two silver nanoparticles with a distance of 2 nm, the electromagnetic field of SERS between the two particles is enhanced by 7.16 × 107. The enhancement of static chemistry also plays a partial enhancement and its enhancement factor is 6. Therefore, the total SERS enhancement, including static chemical strengthening and electromagnetic field enhancement, is Gtotal = GSC × GEM = 4.4 × 108. We also investigated the surface-enhanced resonant Raman scattering (SERRS) of this system theoretically. When the excitation light and p-Thiocre- sol-Ag3 system, the charge-transfer mechanism (chemical enhancement) will also play an important role, the strongest enhancement up to 106. We use the charge density of the p-Thiocresol and Ag clusters under the excitation light charge The visualization of the transfer results is a direct theoretical proof of charge transfer that can reach 1013 for SERRS enhancement, including charge transfer and electromagnetic field enhancement mechanisms.