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Small Angle Scattering



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Table of Contents


The following sections shortly describe the method implemented in DATPOROD, how to run DATPOROD from the command-line on any of the supported platforms and the required input files.


The excluded volume of a particle can be computed from a scattering curve using the Porod equation. Application of this formula directly to the experimental data can be confronted with difficulties related to high noise level at higher angles; therefore the smooth regularized curve produced by GNOM or DATGNOM is used. An appropriate constant K4 is subtracted from each data point to force the s-4 decay of the intensity.

Running datporod


$ datporod [OPTIONS] <GNOMFILE(S)>

OPTIONS known by DATPOROD are described in next section, the 'GNOMFILE' arguments in the section on input files.

Command-line arguments and options

As command line arguments DATPOROD accepts the filename(s) of a GNOM/DATGNOM output, possibly with relative or absolute path components. A mask can be used to match several files.

DATPOROD recognizes following command-line options:

Short optionLong optionDescription
--rg Override the Rg found in the input file.
--i0 Override the I0 found in the input file.
-v --version Print version information and exit.
-h --help Print a summary of arguments and options and exit.

Runtime output

The used Rg, I0, the computed volume estimate and the input file name are printed to stdout.

datporod input files

DATPOROD uses the regularized curve from a GNOM/DATGNOM output file.


$ datporod *compl*.out
  0.273000E+01  0.789100E+01  0.863327E+01  11compl_026.out
  0.309000E+01  0.197100E+02  0.162107E+02  11compl_028.out
  0.357000E+01  0.376500E+02  0.248388E+02  11compl_030.out
  0.389000E+01  0.482800E+02  0.301572E+02  11compl_032.out
  0.356000E+01  0.373700E+02  0.244021E+02  11compl_050.out
  0.297000E+01  0.192600E+02  0.161255E+02  11complex_merge.out
  0.271000E+01  0.108600E+02  0.106667E+02  21compl_020.out
  0.302000E+01  0.186000E+02  0.166231E+02  21compl_022.out
  0.354000E+01  0.280100E+02  0.232878E+02  21compl_049.out

  Last modified: April 11, 2013

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