Bocquet, F.C.
Mercurio, G.
Franke, M.
van Straaten, G.
Weiß, S.
Soubatch, S.
Kumpf, C.
Tautz, F.S.
Torricelli: A software to determine atomic spatial distributions from normal incidence x-ray standing wave data
Computer Physics Communications
Computer Physics Communications
Computer Physics Communications
Computer Physics Communications
235
Normal incidence x-ray standing wave
Photoelectron spectroscopy
Dynamical x-ray diffraction theory
Semi-classical theory of light matter interaction
First-order perturbation theory
Dipole approximation
Dipole–quadrupole approximation
2019
2019
We introduce a software, Torricelli, for the analysis of normal incidence x-ray standing wave data. In particular, given the experimental x-ray reflectivity and photoelectron yield of a data set (photon energy scan), Torricelli provides the corresponding structural parameters. The algorithm and equations on which Torricelli is based are explained here in detail. In particular, the model of the experimental reflectivity takes into account the theoretical reflectivity of the double crystal monochromator as well as the sample crystal, and a Gaussian broadening to account for mosaicity and photon energy spread. If statistical errors are provided together with the photoelectron yield data, these are propagated to produce the statistical errors of the structural parameters. For a more accurate analysis, angle-dependent correction parameters specific to the photoemission process, also beyond the dipole approximation, can be taken into account, especially in the case of non-perfect normal incidence. The obtained structural parameters can be compared, averaged, and displayed in an Argand diagram, along with statistical error bars.
Elsevier
Computer Physics Communications
Articles
10.1016/j.cpc.2018.06.009
English