水的局域结构和谱学特征

Local structure and spectra of liquid water

本文综述了最近十年来利用振动光谱研究液相水微观局域结构的进展.我们系统比较了红外光谱,拉曼光谱和其他谱学技术对水微观局域结构的敏感程度.从实验和理论两方面重点总结了水的红外光谱,拉曼光谱的各种光谱谱峰分解方法及其归属,以及一些非谱峰分解处理方式的特点及相应的对水微观结构的认识.到目前为止,所达到的一个基本共识是,水的局域结构主要是非对称的四氢键结构,具有少量的无氢键或者弱氢键的氧氢共价键(OH键).另外,水的光谱中最明显的谱学特征总是和自由OH存在形式相关.

We review the local structure of liquid water probed by the vibrational spectroscopy in recent ten years. We compare systematically the sensitivity of IR absorption spectroscopy, Raman scattering spectroscopy and other spectroscopies. It is found the Raman spectroscopy is most sensitive to the local structure of liquid water. The decomposition, the assignments of these vibrational spectra, and the local structure from these spectra of water are reviewed in the view point of experiment and theory. The decomposition and the assignment of IR and Raman spectra are very arbitrary, hence some detailed structures based on these analysis are questionable. So far, the local structure is reached an agreement, the asymmetrical four hydrogen bonding dominates the local structure of liquid water, and little free OH and weak hydrogen bonding present in water. The quantum effect of hydrogen atom weaks the local structure of liquid water, which can be observed directly by Raman spectroscopy. The most obvious feature is the spectra of free OH.