A SIMPLE THEORETICAL MODEL OF FIELD EVAPORATION

This work develops a theoretical model of field evaporation by constructing potential energy curves as explicit functions of electric field, charge transfer and distance from the electrical surface. Four separate contributions to the potential energy are considered : i) Electric field, ii) Image potential, iii) Electronic charge transfer and iv) Electronic binding. The final potential energy curve is formed by minimising the energy as a function of q for fixed F and z. This model suggests that the bonding point for a surface atom may be < 0.5Å from the image plane compared to ≃ 1.3Å calculated using a conventional charge exchange model