2023 年 21 巻 2 号 p. 114-120
This paper discusses the recent progress in electron inelastic mean free paths (IMFPs) calculations with the dielectric response function and optical energy loss function (ELF) as key parameters. As a result, it has been found that for most materials, the IMFP values calculated by the various calculation algorithms agreed well each other in the energy region above 300 eV. However, there is a large difference in the energy region under 200 eV. The energy dependencies of IMFPs calculated from optical ELFs could be expressed by the modified Bethe equation in the energies between 50 eV and 200 keV. The material dependence of IMFPs could be expressed by the TPP-2M equation. For IMFP calculations, the treatments and evaluations of the electron exchange effect, the effect of energy gap in the energy loss function, and the associated integral region also remain important issues to be addressed in the future.
