DISSOCIATION DYNAMICS OF DIATOMICS SCATTERED FROM A AG(111) SURFACE - RESONANT AND AUGER NEUTRALIZATION

Dissociative scattering on a Ag(111) crystal surface of neutral and positively charged diatomics (H2*, H2+, He2*, He2+) at low normal incidence energies (E(perpendicular-to) < 1 eV) has been studied by measuring relative velocity distributions of the neutral fragments. The dissociation fragments were recorded by means of a two-particle detector with a condition of coincidence for arrival of both fragments. On taking into account independent straggling of the fragments after dissociation, the spectra are interpreted as resulting from direct dissociation. A comparison with theory is presented. The experimental data support Auger neutralization in the case of helium. For hydrogen we interpret the results in terms of resonant neutralization.