My general research interests concern the computational characterization and theoretical analysis of dynamics in complex systems. Here are some current and past projects.

Reactive Force Field for Proton Transfer

A force field approach - molecular mechanics with proton transfer (MMPT) - is developed to provide an efficient and accurate way to study proton transfer reactions and hydrogen bonding interactions in chemically and biologically relevant systems. MMPT uses parametrized three-dimensional potential energy surfaces fitted to high level ab initio calculations (MP2/6-311++G(d,p)) to describe the interactions within a general DH--A motif where D is the donor, H is the hydrogen and A is the acceptor atom. Together with a standard force field - here, the CHARMM force field is used - specific rules control how bonded interactions on the donor and acceptor side are switched on and off depending on the position of the transferring H-atom (DH--A or D--HA). MMPT is now available in the standard CHARMM code.

Improving Force Field with NMR Observables

NMR observables contain valuable information about structural and conformational dynamics of proteins, and we try to utilize such information in the perspective of force field development. Heterogeneous NMR data, including scalar couplings across hydrogen bonds, chemical shifts, relaxation times T1, and residual dipolar couplings can be computed from MD simulations in explicit solvent. A fitting interface between CHARMM and I-NoLLS is then used to minimize the difference between these ensemble-averaged results and experimentally measured values.

Refs: JCTC, 6, 467

Molecular Modelling of Transition Metal Complexes

We collaborate with Prof. Bernhard Breit's group to investigate the atomistic details of a novel self-assembly transition metal catalysis.

Refs: JACS, 133, 964

Nonlinear Dynamics and Complex Systems

I'm also interested in nonlinear dynamics and complex systems. In my master thesis I proposed a ``dynamical potential" approach to chaotic dynamics in molecular highly excited vibrational states, and used it to study DCO together with Lyapunov exponent and phase space analysis. The dynamical potential approach has been successfully applied to other triatomic molecule systems such as HCO, HCP, DCN, etc.

Refs: Chem. Phys. Lett. 439, 231
dynamical potentials in DCO