INTERACTIONS ENTRE ADATOMES SUR METAUX

Après avoir brièvement rappelé les données expérimentales, on présente une revue de l'état actuel des connaissances théoriques sur les énergies d'interaction entre paires d'atomes chimisorbés sur une surface métallique. On discute les conséquences possibles sur la dissociation des molécules, la nature des surstructures ordonnées et la forme des îlots observés à faible taux de recouvrement.After a brief recall of experimental data, a review is presented on the present state of theoretical knowledge on the pair interaction energies between chemisorbed atoms on a metallic surface. Possible implications on dissociative chemisorption, ordered overlayers and island shapes at low coverage are also discussed

Bandstructure approach to near edge structure

We review the current state of the art in EELS fingerprinting by computer simulation, focusing on the bandstructure approach to the problem. Currently calculations are made using a one electron theory, but we describe in principle the way to go beyond this to include final state effects. We include these effects within the one electron framework using the Slater transition state formula and assess the errors involved. Two examples are then given which illustrate the use of the one electron approximation within density functional theory. Our approach is to combine predicted atomic structure with predicted electronic structure to assist in fingerprinting of complex crystal structures