Open AccessAbout estimation of fitted parameters' statistical uncertainties in EXAFS. Critical approach on usual and Monte Carlo methods
Author(s) -
Curis Emmanuel,
Bénazeth Simone
Publication year - 2005
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049504032261
Subject(s) - monte carlo method , x ray absorption spectroscopy , equivalence (formal languages) , statistical physics , hybrid monte carlo , mathematics , dynamic monte carlo method , nonlinear system , physics , absorption spectroscopy , computational physics , markov chain monte carlo , statistics , optics , quantum mechanics , discrete mathematics
An important step in X‐ray absorption spectroscopy (XAS) analysis is the fitting of a model to the experimental spectra, with a view to obtaining structural parameters. It is important to estimate the errors on these parameters, and three methods are used for this purpose. This article presents the conditions for applying these methods. It is shown that the usual equation is not applicable for fitting in R space or on filtered XAS data; a formula is established to treat these cases, and the equivalence between the usual formula and the brute‐force method is evidenced. Lastly, the problem of the nonlinearity of the XAS models and a comparison with Monte Carlo methods are addressed.