Backward emission of light ions from polyatomic projectiles during keV energy bombardment of solid surfaces

During the bombardment of organic and inorganic targets by keV energy deuterated valine molecular ions and clusters, a backward emission of deuterium ions has been observed. These ions can only come from the projectiles themselves and result from collisions between light and heavy atoms in the projectile upon impact with a solid surface. The average initial velocity of the light ions emitted from the projectile in the backward direction is similar to 2.5 times greater than the average velocity of light secondary ions sputtered from the target surface. The average initial kinetic energy of the "splashed" light ions corresponds to similar to 37.5% of their incident kinetic energy. (C) 1997 Elsevier Science B.V.