液体混合物的缔合现象是一个重要的物理化学问题。一个液体中是否存在缔合体？存在什么样的缔合体？能否通过实验手段将其捕捉或者鉴定出来？这些都是没有彻底解决的问题，严重阻碍了溶液化学的发展。鉴于此，本基金项目拟对超额光谱方法做进一步的拓展，通过研究超额峰位置与溶液浓度间的关系，区分溶剂效应和缔合体生成对光谱的不同影响，提出一种鉴定溶液中缔合体的准则。在发展方法学的基础上，该项目将研究若干二元和假二元液体混合物的缔合性质，鉴定溶液中的缔合体。这将包括含卤键体系、含氢键功能化离子液体体系和仿蛋白体系，研究它们在近惰性溶剂、非质子溶剂和质子溶剂中的自缔合以及交叉缔合行为。对于含卤键体系，将选择多种卤代氟苯，也将研究溴和碘与生物分子间的卤键作用；对含氢键功能化离子液体体系，将选择含腈基离子液体；对于仿蛋白体系，将选择含酰胺键分子和氨基酸。本项目既有方法学上的意义，也将深化人们认识相关体系的物理化学性质。

The phenomenon of association in liquid mixtures is an important academic question in physical chemistry. Are there associates/aggregates in a solution? What is the nature of the associates? Can we identify them experimentally? These are unsolved problems up to now. With these in mind, we propose to develop a method using computation simulation to identify the associates based on the framework of excess spectroscopy. The roadmap is to differentiate the effects of solvation and association on infrared spectra. Experimentally, we will examine a series of binary and quasi-binary liquid mixtures containing representative molecules in the categories of halogen-bonding interactions, properties of ionic liquids, and protein-small molecule interactions. We will try to identify self- and cross-associates of the selected molecules in either inert solvents or protonic/aprotonic solvents. The representative molecules we will examine include halogen derivatives of fluoro-benzene, solutions of bromine and iodine, functionalized ionic liquids, amide-containing molecules, and amino acids. In summary, this research project is important not only in the development of methodology of excess spectroscopy, but also in understanding the basic physicochemical properties of the respective molecules/systems.