Harpooning in scattering of O2 + from Ag(111): Dependence on initial beam energy and direction

Abstract
Harpooning transitions have been observed in collisions of O2 + at energies E i = 100–400 eV from Ag(111) leading to O and O2 ions. Specular scattering is predominant. The degree of dissociation of the negative ions observed seems to scale with E n = E i cos2(θ i ) and depends on the azimuthal angle. It is argued that collision induced dissociation is the major cause of the dissociation observed.