An Feng, Chen Junjie, Hu Xixi, Guo Hua, Xie Daiqian
Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
Kuang Yaming Honors School, Nanjing University, Nanjing 210023, China.
J Phys Chem Lett. 2020 Jun 18;11(12):4768-4773. doi: 10.1021/acs.jpclett.0c01278. Epub 2020 Jun 4.
Derivative couplings near a conical intersection and spin-orbit couplings between different spin states are known to facilitate nonadiabatic transitions in molecular systems. Here, we investigate a prototypical electronic energy transfer process, I() + O(Δ) → I() + O(Σ), which is of great importance for the chemical oxygen-iodine laser. To understand the nonadiabatic dynamics, this multistate process is investigated in full dimensionality with quantum wave packets using diabatic potential energy surfaces coupled by both derivative and spin-orbit couplings, all determined from first principles. A near quantitative agreement with structural, energetic, and kinetic measurements is achieved. Detailed analyses suggest that the nonadiabatic dynamics is largely controlled by derivative coupling near conical intersections, which leads to a small effective barrier and hence a slightly positive temperature dependence of the rate coefficient. The new results should extend our understanding of energy transfer, provide a quantitative basis for numerical simulations of the chemical oxygen-iodine laser, and have important implications in other electronic energy transfer processes.
