Zhang Wen-kai, Wang Hong-fei, Zheng De-sheng
State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, ZhongGuanCun, Beijing, China100080.
Phys Chem Chem Phys. 2006 Sep 21;8(35):4041-52. doi: 10.1039/b608005g. Epub 2006 Aug 10.
Second harmonic generation (SHG) has been proven a uniquely effective technique in the investigation of molecular structure and conformations, as well as dynamics of molecular interfaces. The ability to apply SHG to molecular interface studies depends on the ability to abstract quantitative information from the measurable quantities in the actual SHG experiments. In this review, we try to assess recent developments in the SHG experimental methodologies towards quantitative analysis of the nonlinear optical properties of the achiral molecular interfaces with rotational isotropy along the interface normal. These developments include the methodology for orientational analysis of the SHG experimental data, the experimental approaches for more accurate SHG measurements, and a novel treatment of the symmetry properties of the molecular polarizability tensors in association with the experimentally measurable quantities. In the end, the recent developments on the problem of surface versus bulk contribution in SHG surface studies is discussed. These developments can put SHG on a more solid foundation for molecular interface studies, and to pave the way for better understanding and application of SHG surface studies in general.
二次谐波产生（SHG）已被证明是一种在研究分子结构、构象以及分子界面动力学方面具有独特效果的技术。将SHG应用于分子界面研究的能力取决于从实际SHG实验中的可测量量提取定量信息的能力。在这篇综述中，我们试图评估SHG实验方法在定量分析具有沿界面法线旋转各向同性的非手性分子界面的非线性光学性质方面的最新进展。这些进展包括SHG实验数据的取向分析方法、更精确的SHG测量实验方法，以及与实验可测量量相关联的分子极化率张量对称性质的新处理方法。最后，讨论了SHG表面研究中表面贡献与体相贡献问题的最新进展。这些进展可以为SHG在分子界面研究中奠定更坚实的基础，并为总体上更好地理解和应用SHG表面研究铺平道路。
