碱性品红分子在正、负电性纳米银上的吸附取向

制备了两种不同电性的纳米银粒子的胶体，发现当碱性品红分子分别吸附的在这两种纳米银上时，其表面增强拉曼谱在谱线的强度及谱线数目上均有有明显的不同。在正电性纳米银上，主要是面内模式得到增强，且碱性品红特征峰的强度是I1589>I1524>I1371。而在负电性纳米银上，面内伸缩模式及面外弯曲模式均得到增强，且碱性品红特征峰的强度是I1588<I1520=I1371，通过分析增强谱的差异表明，分子在这两种不同电性胶态纳米银表面上可能分别以垂直及倾斜方式吸附。

Adsorption Orientation of Fuchsine Basic on Negatively and Positively Charged Silver Colloid Particles

Both negatively and positively charged colloids (for short, PCS and NCS) with nano-silver particles were prepared. TheNCSwaspreparedbyusing tannic acid asthe reducing agent forAgNO3 and the PCS was prepared by using trisodium citrate as the reducing agent forAgNO3. The surface charge of these two kinds colloidal silver particles was validated by electrophoresis experiment. Surface enhanced Raman scattering (SERS) from fuchsine basic molecules on the two colloids of nano-silver particles were recorded respectively and compared with each other. The resultsshow that there are some obvious differences on the SERSspectrawhen the molecule was adsorbed on the NCS and PCS. On PCS, the in-plane vibrational modes ring skeletal vibration 968cm-1, ring C-H bend 1178 cm-1, N-phenyl stretching 1370 cm-1, Ring C=Cstretching 1588 cm-1were enhanced.On theother hand, on NCS, both the inplane 348, 914, 968, 1178, 1291, 1370, 1520, 1588 cm-1and out-of-plane 1520, 832, 759, 736,423 cm-1were enhanced. It indicates that the fuchsine basic molecule adsorbs on the two kinds of silver surface in different configuration. The molecule adsorbs on the PCS surface vertically, however tilted on the NCS surface.