CCP6 Renewal: Developing Quantum Dynamics for Large Systems

计算机模拟已经成为帮助理解甚至预测化学实验结果的重要工具。许多基本的过程需要考虑分子的量子力学性质，以便进行真实的模拟。然而，目前，我们无法用量子力学来正确地对待几个以上原子的动力学。因此，人们必须精确地模拟简化的模型系统，或者使用经典分子动力学等近似方法来模拟完整的系统。克服这些限制的一个有效途径是使用量子力学来处理系统的一部分，并使用更近似的方法来处理系统的一部分。这项研究旨在开发一种有前景的新的混合动力学算法，在该算法中，系统不同部分之间的重要但理论上困难的相互作用被严格处理。作为对该方法的测试，我们提出了模拟将水分子分散到蛋白质表面的实验。散射过程将使用全量子力学描述，而蛋白质环境将动态而明确地描述，但更接近。结果应该能在分子水平上洞察溶剂化的本质。

Computer simulations have become essential tools to help understand, and even to predict, the results of chemistry experiments. Many fundamental processes require the quantum mechanical nature of molecules to be taken into account for a realistic simulation. At present, however, we are unable to treat correctly the dynamics of more than a few atoms using quantum mechanics. As a result, one has to simulate either a reduced model system exactly, or the full system using approximate methods such as classical molecular dynamics. A useful route to overcome the limitations is to treat part of a system using quantum mechanics, and part of the system using more approximate methods. The proposed research aims to develop a promising new mixed dynamics algorithm in which the all important, but theoretically difficult, interaction between the different parts of the system is treated rigorously.As a test of the method we propose to simulate experiments that scatter water molecules off the surface of a protein. The scattering process will be described using full quantum mechanics, while the protein environment will be described dynamically and explicitely, but more approximately. Results should give insights into the nature of solvation at the molecular level.