Probing the Potential Energy Surfaces of BrCN- by Dissociative Electron Attachment

Xiao-Fei Gao; Feng An; Hao Li; Jing-Chen Xie; Xu-Dong Wang; Xin Meng; Bin Wu; Dai-Qian Xie; Shan Xi Tian

doi:10.1021/acs.jpclett.0c02991

Probing the Potential Energy Surfaces of BrCN^- by Dissociative Electron Attachment

J Phys Chem Lett. 2020 Nov 5;11(21):9110-9116. doi: 10.1021/acs.jpclett.0c02991. Epub 2020 Oct 13.

Authors

Xiao-Fei Gao¹, Feng An², Hao Li¹, Jing-Chen Xie¹, Xu-Dong Wang¹, Xin Meng¹, Bin Wu¹, Dai-Qian Xie^{2

3}, Shan Xi Tian^{1

3}

Affiliations

¹ Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China.
² Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Institute of Theoretical and Computational Chemistry, Nanjing University, Nanjing 210023, China.
³ Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), University of Science and Technology of China, Hefei 230026, China.

PMID: 33049137
DOI: 10.1021/acs.jpclett.0c02991

Abstract

State coupling certainly determines the topologic features of the molecular potential energy surface (PES) and potentially diversifies chemical reaction pathways. Here we report the new PESs of BrCN^- in the low-lying electronic states that are distinctly different from the previous predictions in the short Br-CN bond region but validated by the high-resolution ion velocity imaging measurements of low-energy dissociative electron attachment (DEA) to BrCN. Besides the vibrating CN^- ions produced in the fast Br-CN bond stretching motions, we confirm that the ro-vibrating CN^- ions with a nearly isotropic angular distribution are produced by receiving a torque in the combinational motion of Br-CN bond bending and stretching. The latter process is closely related to the potential well of BrCN^- at the first excited state A²Π_3/2 that arises from the Π-Σ state couplings. Our findings not only suggest that the PESs of other anionic cyanogen halides are in dire need of reexamination but also show that ion velocity imaging of the DEA process is a powerful experimental method for evaluating the theoretical PESs of molecular anions.