Practical Electron Microscopy and Database

Hydrogenic model and Hartree-Slater model give good results for evaluating the K-shell excitation cross-section. A comparison of K-edge and cross-section profiles for low atomic number (Z) elements [1] shows that the cross-section profiles present the K-edge roughly for an edge where the fine structures are important, e.g. for boron nitride (BN).

Figure 4614 shows the cross section of K-shell ionization process in Al as a function of the incident electron energy at the scattering angles of ~ 0°. For comparison, the figure also shows cross sections for the elastic and various inelastic scattering processes.

Figure 4614. Cross sections for the elastic and various inelastic scattering processes in Al as a function of
the incident electron energy at scattering angles of ~ 0°.

Based on a non-relativistic theory, Allen and Rossouw [2] calculated the inelastic object functions for K-shell ionization. The calculated object functions for the K-shell excitations of some elements such as Te, Cd, As and Ga indicate that the localization of the object is less than 1 Å [3].

[1] Ahn C. and Rez P., Ultramicroscopy 17 (1985) 105.
[2] L.J. Allen, C.J. Rossouw, Phys. Rev. B 42 (1990) 11644–11654.
[3] N.D. Browning, S.J. Pennycook, Microbeam Anal. 2 (1993) 81–89.