利用光吸收的时间效应实现银胶—分子系统中sp和CT吸收带的分离

The Separation to CT and sp Bands of Optical Absorption in Silver-molecule system by OSMA

本文利用OMA能够记录快速时间过程的特点对银胶—吡啶体系的光吸收特性的时间效应进行了观察,发现吸收谱上先后出现了两个强度增长速度不同的新吸收带。初步分析认为,这两个新吸收带分别对应于银胶凝聚的sp吸收带和银表面—分子间电荷转移的CT吸收带。在达到稳定状态时,sp吸收带完全淹没了CT吸收带,这与一般通过UV-visible观察到的该体系稳定态的吸收谱有明显不同。从而为在吸收谱上明确分离SERS的电磁和化学两大增强机制提供了直接实验证据。

The rapid variation of light absorption spectra of Ag sol-Pyridine system, which more different to the case of UV-visible absorption spectra that obtained from the stable state of this system, was observed. It was found that two new bands have appeared one after another and grew with the time in different scales, We believed that these two bands were respectively assigned to the charge-transition (CT) band which occured between Ag surfaces-pyridine and the sp band that from aggregated Ag sol. It is important to the investigation of SERS mechanisms.