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SAXS from P(r)

Posted: 2019.08.16 13:55
by shoma
Hi all,

just a quick question - is there a tool in ATSAS package that allows calculating the SAXS curve from a given P(r) function, opposite direction that gnom does?

Thank you in advance!


Posted: 2019.08.19 08:42
by AL
Sure, it is called pddffit.

Code: Select all

$ pddffit --help
Usage: pddffit <PDDFFILE> <DATFILE> [OPTION]

Fits a pair distance distribution function to experimental data.

Known Options:
  -o, --output=FILE  write the output to this file instead of stdout
  -v, --version      print version information and exit
  -h, --help         print this help and exit

Report bugs to <>.
The PDDFFILE should be in a three-column format. The intensity calculated from the p(r) will be in the fourth column of the output file.

Re: SAXS from P(r)

Posted: 2019.08.19 13:26
by shoma
Hi AL, thank you for the quick and kind answer.

pddffit asks for two arguments, P(r) and experimental curve?
can I do something if I have only P(r) function, but not any curve. And I want to predict SAXS curve only from P(r).

Re: pddffit

Posted: 2019.08.20 13:33
by AL
You may take any "template" curve, run pddffit, then remove the second and third column from the output file.