Étude d'une surface de NaCl sous bombardement électronique de basse énergie: Influence de l'irradiation sur la charge de la surface

The preliminary results of angular low energy electron spectroscopy studies on cleaved NaCl surfaces are reported. The first problem to solve was to prevent the sample from charging, that is, to prevent the secondary emission coefficient from getting lower than unit. The case δ<1 is shown to be due to the dissociation of NaCl under bombardment. The dissociation was stopped when cooling the sample to about 125 °K. Metallic Na particles are formed on the surface under irradiation. The energy loss spectrum shows absorption bands at 1.5, 2.7, and 3.8eV. These bands are characteristic of the dissociation rate, dependent on sample temperature and on time of irradiation.