Differential inverse inelastic mean free path and differential surface excitation probability retrieval from electron energy loss spectra

Abstract

Quantitative interpretation of the electron spectroscopy data requires the information on differential inverse inelastic mean free paths (DIIMFP) and differential surface excitation probabilities (DSEP). In this paper, we test an algorithm of extracting DIIMFP and DSEP from reflected electron energy loss spectra (REELS) and photo-electron spectra (PES) in which the desired functions are parametrized on the base of linear respond theory. Unknown parameters are found by using the fitting procedure. To account for surface excitations, the investigated samples are considered as multi-layer systems. Simulations of REELS and PES are performed by making use of the partial intensity approach. The partial intensities for the reflection function and the photo-electron density flux are computed on the base of the invariant imbedding method. Extracted DIIMFPs and DSEPs are compared with those obtained by other authors. Finally, REELS and PES spectra for Be, Mg, Al, Si, Nb and W are computed using the retrieved DIIMFPs and DSEPs, and compared with the experimental spectra. All comparisons show good agreement.

Simulating the Feasibility of Using Liquid Micro-Jets for Determining Electron–Liquid Scattering Cross-Sections

“…The inclusion of energy dependencies was conceptually treated [ 79 ], with strict delta function requirements placed on both the source and detector, in order to derive total and differential cross-sections. In other studies, sufficiently thin (10–100 ) solid films were used to derive surface and bulk inelastic mean free paths [ 80 , 81 , 82 ], assuming a knowledge of the elastic cross-section. Likewise, cross-sections for amorphous ice films were derived under a two-stream assumption, along with a variation of film thickness between 0 and [ 16 , 83 , 84 ].…”

Optical constants of organic insulators in the UV range extracted from reflection electron energy loss spectra

“…It is not clear how or whether at all the software of Tahir and Tougaard is taking this into account. Afanas'ev et al 23,24 proposed another approach of deriving the normalised DIIMFP aimed to fit entire REELS spectra instead of using any deconvolution procedure. This method implies that in each fitting step, the normalised DIIMFP and also the normalised DSEP are refined by varying parameters needed for their calculations until the experimental spectrum is reproduced with sufficient accuracy.…”

Application of the Photometric Theory of the Radiance Field in the Problems of Electron Scattering

“…The main advantage of approximate analytical solutions consists in the high computational speed, which is a prerequisite for solving inverse problems by the fitting procedure. Note that the latter is the most robust approach to deal with ill-posed problems of mathematical physics, namely, remote sensing retrieval and quantitative composition analysis using electron spectroscopy [26,27].…”