银溶胶体系表面增强拉曼散射光谱的溶剂效应  

The Effect of Solvent on Surface Enhanced Raman Scattering Spectra of Colloidal Silver

作　　者：何张飞[1] 顾仁敖[1] 

机构地区：[1]苏州大学化学系,苏州215006

出　　处：《高等学校化学学报》1993年第1期102-105,共4页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金

摘　　要：研究了银溶胶体系表面增强拉曼散射光谱的溶剂效应,发现在不同的溶剂中,银溶胶的聚集状态不同,当胶粒带电荷时,溶剂还能影响分子在胶粒表面的吸附,溶剂通过改变胶粒的聚集状态及分子在胶粒上的吸附这两个因素影响银溶胶体系的SERS光谱。This paper reports the effect of solvent on the surface enhanced Raman scattering (SERS) spectra of colloidal silver, using 2-aminobenzimidazole(BIMNH2) as a probe molecule. The absorption spectra indicate that the state of aggregation of colloidal silver is not alike in different solvents, the degree of dispersion of colloidal silver in different solvents always increases in the. order of C2H5OH, C2H5OC2H5, CH3OH, H2O, colloidal silver is more dispersed in CHCl3 than in CH2C12, CC14, the latter two systems are almost the same. Different states of aggregation will give the different intensities of SERS. Experiment also indicates that the degree of dispersion of colloidal silver is always larger in ' mixed solvent than in single solvent. Besides, if l;he colloidal particle is positive-charged, the negative-charged pole of nearby the solvent molecule will be towards the colloidal particle, and this pole will repel π-electron of BIMNH2, so the adsorption of probe molecule on the colloidal particle will be affected by solvents, mainly in quantity and intensity of adsorption. Thus, in these cases, the intensity of SERS will be related to not only the state of aggregation of colloidal silver, but also the dipole moment of solvent. The increase of dipole moment of solvent favors the SERS of colloidal silver. The solvent affects the intensity of SERS of colloidal silver through these two factors. We also discover that the bands of SERS spectra do not shift in different solvents, and the ratio of intensity of bands does not change, too. Those facts make clear that the orientation of probe molecule on colloidal silver does not change in different solvents.

关 键 词：银溶胶 溶剂效应 SERS 

分 类 号：O648.16[理学—物理化学]