A collision process responsible for widespread formation of H anions

International audienceThe hydride ion H− is widely understood to play a major role in many processes important for physics, cosmology, astrophysics and chemistry. Here we report that H- ions can be formed by collision-induced fragmentation of molecules containing hydrogen and heavier nuclei. We observed H− emission from OH+ + Ar and OH+ + acetone collisions at the energy of 7 keV. Our data reveal a process of electron-grabbing by fast hydrogen fragments emitted in hard collisions with large momentum transfer between atomic cores