Formation of beryllium-hydrogen ions in chemical sputtering from 20 to 420eV

•A Be surface is sputtered by D2+ with impact energies from 20 to 420 eV, different temperatures, flux and adsorbate coverage.•All secondary ion species are resolved by time-of-flight mass spectrometry.•Two seperate reaction channels forming beryllium-hydrogen ions have been resolved.•There is a direct reaction of the projectile with the surface, yielding a high ratio BeD+/Be+ ≈ 3 at only 20 eV D2+ impact.•BeH+ can also be created from hydrogen-containing surface adsorbate, most efficiently from water.•There is no evidence found, that the projectile reaction relies on prior D implantation in the bulk Be.