Electron emission from carbon induced by the ions C+, O+, CO+ and O2+

The secondary electron yield from carbon induced by the ions C+, O+, CO+ and O2+ has been measured as a function of ion energy in the range of 2 to 20 keV. It has been observed that electron yield from carbon increases with projectile energy. By comparing electron yields induced by equally fast atomic and molecular projectiles, a molecular effect as a yield reduction has been observed. The measured molecular effect was stronger than the predictions of sweeping-out-electron model.