Regular Article

Dissociation of NH₃²⁺ induced by collision of 300 eV electrons with NH₃

¹ Institute of Modern Physics, Fudan University, Shanghai 200433, P.R. China
² Key Laboratory of Nuclear Physics and Ion-Beam Application (MOE), Fudan University, Shanghai 200433, P.R. China
³ School of Mathematics, Physics and Information Engineering, Jiaxing University, Jiaxing 314001, P.R. China

^a e-mail: brwei@fudan.edu.cn
^b e-mail: zyclay@outlook.com

Received: 19 February 2020
Received in final form: 20 May 2020
Published online: 25 June 2020

Abstract

The dissociation of ammonia dications induced by 300 eV electron impact has been studied using a cold target recoil-ion momentum spectroscopy. Three regimes were found in the evolution of the produced NH₃²⁺ ions, i.e. stable (long-lived), slowly dissociating (metastable), and promptly dissociating. Multiple dissociation channels of NH₃²⁺ have been distinguished and identified by ion–ion coincidence technique. The kinetic energy release of the deprotonation dissociation channel NH₃²⁺ → H⁺ + NH₂⁺ and the bond-rearrangement channel NH₃²⁺ → H₂⁺ + NH⁺ have been obtained. The dynamic information and complex fragmentation pathways were analyzed by combining Dalitz plot and Newton diagram for the three-body dissociation channel NH₃²⁺ → H⁺ + NH⁺ + H. Strong correlation between the dynamic processes of H⁺, H loss, and the kinetic energy release was found.