High negative ion yield from light molecule scattering

Abstract

Molecular oxygen and hydrogen ions were scattered at grazing incidence from several diamond-like carbon (DLC) surfaces in the energy range from 190eV to 2400eV. Most surfaces were hydrogen terminated. For incident positive oxygen ions, scattered negative ion fractions of up to 33% were recorded, and for incident positive hydrogen ions, negative ion fractions of more than 5% were measured. These values are among the highest ever reported, especially for oxygen. They have been matched only by results of scattering experiments using a hydrogen terminated surface of natural diamond.