Formation of negative hydrogen ions in 7-keV OH+ + Ar and OH+ + acetone collisions: a general process for H-bearing molecular species

TL;DR

This study reveals that negative hydrogen ions (H-) are formed in keV collisions involving hydroxyl cations and acetone, through a process of molecular fragmentation and electron capture, impacting astrophysical and atmospheric chemistry.

Contribution

It demonstrates a general mechanism for H- formation in collisions of H-bearing molecules, expanding understanding of ion formation in planetary and astrophysical environments.

Findings

H- ions are produced via molecular fragmentation and electron capture.

The process occurs in collisions at keV energies with hydroxyl cations and acetone.

This mechanism may influence reaction networks in atmospheres and space environments.

Abstract

We demonstrate that the formation of negative hydrogen ions (H-) occurs in a wide class of atomic and molecular collisions. In our experiments, H- emission from hydroxyl cations and acetone molecules was observed in keV-energy collisions. We show that hydride (H-) anions are formed via direct collisional fragmentation of molecules, followed by electron grabbing by fast hydrogen fragments. Such general mechanism in hydrogen-containing molecules may significantly influence reaction networks in planetary atmospheres and astrophysical media and new reaction pathways may have to be added in radiolysis studies.