中文摘要：

为确定表面增强拉曼光谱中某些有争议的弱振动模式是来自高阶的影响还是分子基团对称性变化的影响，本文以1，4-苯二硫醇作为探针分子提供了一种实验验证的框架方法．光谱实验显示，观测到的有争议的弱振动模式并不是来自高阶的影响，而是分子基团对称性变化所致．我们的实验框架方法很容易拓展开来，如用于研究其它波长激光激发的类似体系或有机分子搭接的分子结．

英文摘要：

The origin of weak ambiguous vibrational modes in surface enhanced Raman scattering （SERS）, i.e., from the high-order effect or symmetry change using 1,4-benzenedithiol （BDT） as a probe, is investigated. Weak ambiguous vibrational modes are caused by symmetry change rather than high-order effect. The experimental method can be extended, e.g., to similar systems excited by lasers with different wavelengths, or microelectronic junctions bridged by organic molecules.