电解质在水溶液中是以自由离子形式存在还是形成离子团簇是受到广泛关注且备受争议的一个课题，而它是理解许多重要问题的关键。二维光谱技术是探测离子团簇化结构及其相关动力学过程的重要研究手段。本项目旨在通过发展一套包含发色团对环境的反馈作用的半经典分子动力学理论结合二维光谱理论计算方法研究水溶液中离子团簇化过程的微观机理。我们将结合激子模型和薛定谔方程数值积分(NISE)方法，并引入发色基团对环境的反馈作用来实现具体实验体系的二维光谱计算。通过建立一些合理的微观模型，得到与实验可以定量对比的二维光谱信号，从而揭示影响离子团簇的存在与否、浓度和结构的微观机理以及形成离子团簇的离子间作用本质，为理解基于离子团簇化的蛋白质变性以及离子通道等实验和应用研究提供理论依据和指导。

Whether electrolytes exist as free ions or clusters in aqueous solution is an important issue which is widespread attention and controversial. It has been considered as a key issue for understanding many important problems. Ultrafast two-dimensional (2D) techniques is crucial for detecting ion cluster structures and its related dynamical process. This proposal aims to develop a set of semi-classical molecular dynamics theory that contains the feedback of the quantum system on the classical environment. It will combine with 2D spectrum calculation theory for understanding the microscopic mechanism of the ion clustering process. We will bring out the 2D spectrum calculation of specific experimental system by combining with exciton model, Numerical Integral of Schrodinger Equation (NISE) method and including the feedback of the quantum system on the classical environment.We will get some 2D spectrum signals that could be quantitatively compared with experimental 2D spectrum through the establishment of a few reasonable microscopic models, for revealing the microscopic mechanism of the ion clusters's existing or not, concentration and structure as well as the essence of the interactions between ions. This proposal will provide theoretical basis and guidance for experiments and application studies such as protein denaturation by salts and ion concentration dependent properties of ion channels that based on ion clustering.