Proton stopping in ultrathin films

This talk will survey the predicted trends in proton stopping traceable to the effects of number of layers (quantum size effects), structure and reconstruction, and chemical binding for clean, ultrathin (1-5 layers). First principles energy optimization of the ultrathin film structure is followed by calculation of stopping cross sections in the First Born approximation (normal incidence) via orbitally adapted variants of the kinetic theory of stopping and the local plasma approximation. The justification of these approximations and their physical implications will be considered briefly. Results for Li, LiF (in both normal and highly strained configurations), unreconstructed diamond, and graphite will be presented and their systematics discussed. The most evident trend is that the ultrathin film stopping is quite distinct from bulk stopping even though the latter is usually conceptualized and presented as a zero-thickness limit