PLANAR CHANNELING OF ELECTRONS AND POSITRONS IN CRYSTALS - LOCAL DENSITY CALCULATION OF CONTINUUM POTENTIAL AND CHANNELING RADIATION SPECTRUM

Within the local-density approximation to the density functional formulation and using the linear muffin-tin Orbitals (LMTO) method, we calculate the planar-averaged potential seen by electrons and positrons channeled along (110) planes of diamond, Si and Ge crystals. The calculated potentials are in excellent agreement with the empirically derived potentials. This shows the applicability of the state-of-the-art local-density calculations to the channeling problem. For the crystal considered, our potentials are very similar to the ones obtained by superposition of the atomic Hartree-Fock potentials but are different from the potentials obtained from superposition of the atomic Thomas-Fermi statistical (Molière) potentials. Frequencies of emitted radiation from planar-channeled electrons and positrons are also calculated and compared with experiments. It is expected that the solid-state effects, i.e. the effect of charge redistribution caused by the solid formation, would be significant for ionic solids. © 1990.