pawley_refinement_and_background_fitting
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pawley_refinement_and_background_fitting [2011/08/25 18:14] – alancoelho | pawley_refinement_and_background_fitting [2022/11/03 15:08] (current) – external edit 127.0.0.1 | ||
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+ | ====== Pawley Refinement and Background Fitting ====== | ||
+ | As a follow on to a discussion on the Rietveld mailing list regarding how to determine the background in a Pawley Refinement with heavily overlapped peaks. | ||
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+ | Often the background seems unreasonably low or just wrong. The reason is that there' | ||
+ | |||
+ | <code topas> | ||
+ | { | ||
+ | #m_argu c | ||
+ | c v | ||
+ | = c^2; | ||
+ | } | ||
+ | penalties_weighting_K1 .01 | ||
+ | xdd... | ||
+ | | ||
+ | ... | ||
+ | load hkl_m_d_th2 I penalty | ||
+ | { | ||
+ | | ||
+ | | ||
+ | |||
+ | The value for penalties_weighting_K1 .01 is a little arbitrary. Basically anything that brings the high angle backgroud up to something that looks reasonable. The higher the value the smaller the intensites become and the higher the bkg. | ||
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+ | Using the above approach on test_examples\Pawley1.inp (see the attached I-Penalty.inp) brings the background up a little at high angles. This is not a great example for testing I_Penalty but it does show the effect. | ||
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+ | Note also that the bootstrap_errors can be used to determine the range in values for the intensities. | ||
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+ | | ||
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+ | --- // |