High-Resolution Measurements of the NitrogenK−LLAuger Transitions of Chemisorbed Ammonia on a Molybdenum Surface

Abstract

Distinct "chemical effects" were observed among high-resolution, nonderivative, nitrogen $K-LL$ Auger-electron distributions from chemisorbed N${\mathrm{H}}_3$ on molybdenum surfaces and gaseous N${\mathrm{H}}_3$, which depend on the electronic structures of the adsorbed species. A calculation in the semiempirical "equivalent-core approximation," based on photoelectron data, revealed the origins of the fine structure in the observed Auger spectra. It is concluded that N${\mathrm{H}}_3$ is chemisorbed as a ${\mathrm{H}}_{-\mathrm{Mo}}--{\mathrm{N}}_{-\mathrm{Mo}}{\mathrm{H}}_{x<~2}$ dissociative configuration at about room temperature and the surface nitride is formed at 450°C.