44056-AC6
Quantitative Quantum Dynamics Study of Polyatomic Reactions
Our recent study finds that accurate quantum dynamics properties for chemical reaction systems involving large molecules (larger than four atoms) can be reproduced using the SVRT (semi-rigid vibrating rotor target) model in reduced dimensional space, when zero point energies associated with the neglected degrees-of-freedom can be properly corrected. This has been tested on the benchmark H + CH4 reaction and recently on the H + NH3 reaction. This really points out a practical way to carry out accurate quantum dynamics study for polyatomic reactions in reduced dimensional space using the general SVRT model in a finite dimensional space. This will make it possible for truly ab initio quantum dynamics study of polyatomic reaction by combining with high-level quantum chemistry calculation to generate global potential energy surfaces in a finite dimensions (4 to 5 dimensions). In order to get accurate reaction threshold energies, one needs to perform more thorough analysis and computation of zero point energies for only part of the degrees-of-freedom that are explicitly neglected in the SVRT model. In order to do that, we need to develop a more elaborate numerical procedure to get more accurate zero point energies for these neglected coordinates. This project is currently ongoing in my group. Hopefully, we will be able to develop a complete strategy for ab initio quantum dynamics study of polyatomic reaction dynamics, complete with ab initio calculation of potential energy surface and quantum dynamics calculation in finite dimensional space, coupled with an elaborate procedure to correct the zero point energy effect for the neglected degrees-of-freedom.
