CCP6 Renewal: Developing Quantum Dynamics for Large Systems

Computer simulations have become essential tools to help understand, and even to predict, the results of chemistry experiments. Many fundamental processes require the quantum mecahnical nature of molecules to be taken into account for a realistic simulation. At present, however, we are unable to correctly treat the dynamics of more than a few atoms using quantum mechanics. As a result, typically one has to either simulate a reduced model system exactly, or the full system using approximate methods such as classical molecular dynamics. A useful, alternative, 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 parts of the system is treated rigorously.As a test of the method we propose to simulate experiments that scatter water molecules of 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.