报告题目：分子模拟技术进展——力场和动力学中的量子效应(Advanced technologies in molecular simulations: quantum effects in force field and dynamics)
报 告 人：Yongle Li 李永乐博士 纽约大学
报告地点：校本部G309
报告时间：2015年1月26日（周一）10:00
主办部门：理学院物理系、量子与分子结构国际中心（ICQMS）
邀请人：任伟、Jeffrey Reimers
报告摘要：The ambition of explaining and predicting the behaviors of complicated systems in biology and other areas by computer simulation is unlimited. And to achieve this goal is also the major task for researchers in computational science.

In this presentation, two applications of the advanced technologies in molecular simulations are reported. The first is fragmented molecular conjugated caps method based advanced protein specific charge (MFCC-APPC) molecular dynamics (MD) for simulating metalloprotein, the other is path-integral based ring-polymer molecular dynamics (RPMD) for simulating chemical reactions.

The MFCC method is a linear-scale quantum chemical method to calculate the electronic structure for the entire biomolecules. With its help, the partial charge of each atom in the protein can be obtained efficiently. These charges are named protein specified charge (PPC), and can reflect the quantum polarization properly in MD simulations. Further development of MFCC-PPC (advanced PPC, APPC), using on-the-fly fitted PPCs during MD, can reflect the dynamical polarization, and so more accurate dynamic properties of proteins. The applied system is a designed metalloprotein serving as a scaffold of oxidation reaction relating oxygen, and it contains asymmetric zinc binding group that is hard to simulate by conventional MD. With the help of APPC, the dynamics of this protein is correctly revealed.

On the other hand, for chemical reactions, since there are tunneling effects and zero point energy (ZPE) cannot be ignored, quantum dynamics must be used. Other than conventional memory-consuming wave packet method, the path-integral based method, RPMD, uses only trajectories to simulate the quantum effect. With the help of RPMD, one can achieve the calculation in high dimension much efficiently. The applications of RPMD contain high dimensional abstract reaction systems H/D/Mu/O/Cl/OH+CH4, and low barrier or barrier-less insertion reaction system N/O+H2. In all these cases, RPMD gives correct dynamics and rate coefficients.