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Hello Maxim, You can use Fourier filtering technique. 1. Preliminary refining background with a "simple polynomical" function set IPL (ppl) = 2. This generates the background-file FILE.BAC 2. Set NBCKGD (Nba) = -2 Set the value of Window for Fourier filtering, FWINDOW "The value of FWINDOW must be much greater than the number of points subtended by the base of a single Bragg reflections in the widest region (a factor greater than five, at least!)" Remove the lines with polynomical coefficients and their codes. 3. Run a refinement. The background will be ajusted iteratively while keeping IPL (ppl) = 2, otherwise put IPL (ppl) = 0 (changes will not be written to FILE.BAC). For details look to Fullprof User's manual. MVL> Dear Rietveld list subscribers, MVL> I am sorry for a probably too basic question, but: MVL> I would be grateful if one could suggest a "preferred" way of treating the MVL> background in Fullprof. Because "simple polynomial" often doesn't work even MVL> in the case of simple low-angle upturn, Chebyschev polynomials are not MVL> implemented (to my knowledge), and point-to-point is not very convenient to MVL> handle (even with refineable values). MVL> Sincerely, Maxim. MVL> __________________________________ MVL> Maxim V. Lobanov
