Negatively and positively charged oxygen ion formation in collisions of positively charged projectiles with O-2 molecules in the energy range 50-350 keV

摘要

Absolute cross sections for positive and negative ion fragments formed from O-2 molecules following collisions with H+, H-2(+), He+, and Ar+ projectiles in the energy range 50-350 keV are presented. Cross sections for negatively charged secondary ions are much smaller (approximate to 10(-18) cm(2)) compared to those for positively charged fragments. The non-dissociative formation of negatively charged O-2(-) ions results from an electron transfer collision with the projectile. The impact energy dependence shows that the collision cross section for O-2(-) formation strongly depends on the type of projectile involved.