ELECTRONIC-ENERGY LOSS OF SLOW PROTONS CHANNELED IN METALS

The electronic energy loss for low-velocity protons channeled in the [ 100] direction of single-crystal Au and Al is calculated. The proton t rajectories are determined by solving the equation of motion. In the p roton dynamics two forces are included, a repulsive term arising from the nuclei and core electrons and a friction ford, depending on proton velocity, arising from the valence electrons. The repulsive force on the proton is evaluated using a superposition of conservative potentia ls. The friction coefficient is evaluated by using the local density o f valence electrons, and a quantum-mechanical transport cross-section approach with a self-consistent model based on Friedel's sum rule. The results allow us to describe the nonlinear behavior of energy loss wi th ion velocity observed experimentally in Au, as well as the linear b ehavior observed in Al. [S1050-2947(97)05311-0].