Journal Article

Revealing umbrella bending as a reporter mode in the D+CH 4 reaction

Li, Fan, Zhu, Jikai, Zhang, Dong H, Zhang, Yu, Wang, Tao, Yang, Xueming, Wang, Xingan, Manthe, Uwe, Jin, Mengda, Wang, Ziwei, Yang, Tiangang, Zhao, Bin, Yu, Shanshan, Tan, Yuxin, Liu, Shu, Yuan, Daofu, Luo, Chang, Chen, Wentao

2025

Overview

How the non-reacting moiety of a molecule influences a polyatomic reaction has been a topic of much research interest. Here we present a comprehensive investigation of the D + CH  → HD + CH reaction, a benchmark polyatomic elementary reaction with CH as the non-reacting moiety, employing a high-resolution crossed molecular beams apparatus and an accurate seven-dimensional wave packet method. An interesting angular distribution of the CH (v' = 1) product umbrella bending vibrational state is observed to scatter more in the sideways direction than the CH (v' = 0) one. By monitoring the wave functions on a dividing surface in the transition state region, the CH umbrella bending mode is established as a reporter mode that faithfully reveals how the D atom dynamically approaches CH at different total angular momenta or impact parameters. This discovery of the reporter mode provides an opportunity for the detailed study of polyatomic reaction dynamics.