XEF-DOT, AND OTHER UNUSUAL IONS GENERATED BY REACTIONS OF HYPERTHERMAL ION-BEAMS AT SELF-ASSEMBLED MONOLAYER SURFACES(, IF+CENTER)

Collisions of atomic and molecular ions (I+, Xe+; CH3I+; I2+.) with se lf-assembled fluoroalkyl-monolayer surfaces result in reactions involv ing the net transfer of fluorine atoms or fluorocarbon radicals from t he surface to the projectile ions. The scattered products, which inclu de unusual ionic species such as IF+; IF2+, CFI+; CF2I+, I2F+, and XeF +, are generated in endothermic ion-surface reactions. These reactions are not observed when the collision partner is a gas-phase (rather th an a surface-bound) perfluoroalkane. Evidence is presented which sugge sts that in some cases molecular projectiles undergo surface-induced d issociation to yield atomic species which subsequently react with the surface. Fluorine abstraction is favored for projectiles containing hi ghly polarizable elements.