Powder dictionary (pdCIF) version 1.0.1

_pd_proc_ls_background_function

Definition:

   Description of the background treatment mechanism used to
   fit the data set.

   For refinements where the background is computed as a
   function that is fitted to minimize the difference between 
   the observed and calculated patterns, it is
   recommended that in addition to a description of the
   function (e.g. Chebychev polynomial), the actual equation(s)
   used are included in TeX, or a programming language such
   as Fortran or C. Include also the values used for the
   coefficients used in the background function with their
   s.u.'s. The background values for each data point
   computed from the function should be specified in
   _pd_proc_intensity_bkg_calc.

   If background correction is performed using extrapolation
   from a set of points at fixed locations, these points
   should be defined using _pd_proc_intensity_bkg_fix, and
   _pd_proc_ls_background_function should indicate the
   extrapolation method (linear extrapolation, spline etc.).
   _pd_proc_ls_background_function should also indicate how the
   points were determined (automatically, by visual estimation
   etc.) and whether the values were refined to improve the
   agreement. The extrapolated background intensity value for
   each data point should be specified in
   _pd_proc_intensity_bkg_calc.

Type: char

Category: pd_proc_ls