由于传统的分子力场基于平均场近似，缺乏静电极化和电荷转移效应，使得力场对水溶液的描述精度有限，模拟得到的水溶液的动力学性质与实验结果不一致。近年来，项目申请人发展了基于分块的线性标度量子化学方法来计算大分子体系的能量等理化性质，并且将该方法与分子动力学模拟相结合，实现了大分子体系的从头算分子动力学模拟。本项目将把分块量子化学方法应用于水溶液中相互作用动力学的量子研究，内容包括：1）基于分块的MP2方法进行液态水的从头算分子动力学模拟，并对其动态结构和性质进行精确预测；2）基于分块量子化学方法，对盐溶液中离子对水的作用机制在MP2水平上进行第一性原理研究；3）通过从头算分子动力学模拟液态水和盐溶液在不同温度下的动态性质；4）蛋白质与表面结合水的相互作用动力学的量子研究。我们将应用新方法解决传统力场研究水溶液中相互作用动力学方面存在的问题，把量子化学方法推广到大分子体系的精确动态性质模拟。

Due to the lack of electronic polarization and charge transfer effect in classical force fields, the predicted properties of water solutions based on classical molecular simulation using force fields have large deviations from experimental results. Recently, we have developed a linear-scaling quantum chemistry method based on fragmentation approach for energy and property calculations on large systems. We further combined this fragment-based quantum chemistry method with molecular dynamics simulation, and developed an ab initio molecular dynamics (AIMD) program for first-principle simulation on macromolecules. In this project, we will carry out quantum studies of interaction dynamics in water solutions using AIMD. The project includes, 1) AIMD simulation of liquid water based on fragment-based second-order many-body perturbation theory (MP2) towards its accurate property prediction. 2) AIMD simulation of salt solutions based on fragment-based MP2 method for study of the interaction mechanism between ions and water molecules. 3) AIMD simulation of the dynamical properties of liquid water and salt solutions at different temperatures. 4) Quantum studies of interaction dynamics between proteins and water molecules on the protein surface. Our goal is to accurate simulation of dynamical properties of water solutions using fragment-based ab initio molecular dynamics, which can also be applied to other complex systems in the near future.