<* $Id: xnd_exe.html,v 2000/00/14 09:36:00 berar Exp $ *> Examples files.

Examples files.

xnd top Next file Previous file



Very short example without data creating a simulated pattern. It is a short way to verify if xnd runs and finds its default files.


This a input file to be used the the data file xnd_2.dat.
a neutron data file example with its data file 5400 points, 39 variables (28 parametres), 4 cycles max

Rwp=0.0897 Rp=0.0681 S : 5580 GoF 1.02
The current xnd_2.k file can use the new file structure, however the old example file renamed "xnd_2_1.k" should give the same result.


xnd_3.k + xnd_3.dat a x-ray (generator) data file example with its data file Rwp=0.1454 Rp=0.1133 S : 15888.63 / 1.81
This file is still an old style input file but the new file will be written according to xnd_1.2 style.


xnd_4.k + xnd_4.dat a neutron data file example for incomensurate phase


example of input file with temperature dependancies


xnd_6.k + xnd_6.dat a x-ray data file example with phase profiles


xnd_7.k + xnd_7.dat short file for single line fitting


short file generating lines on simulated pattern


short file simulating quasi crystal pattern


example of input file for a composite structure

Intensities and scale factor

Some applications need to known the absolute intensity received by the sample. The following lines show how such a calculation can be done using xnd scale factor. It uses the relation between intensity and flux as described in a paper from Suorti (Acta Cryst A41 (1985) p413), the definition of functions in xnd. Note that the coefficient 180/Pi arises from the fact that angles in data file are the degrees and therefore the integrated intensities.
The relation between the flux No and the scale factor Scale can be written as :
No = 32 Pi^2 Scale Mu Vc^2 / (180 Eff RSlit VDiv Re^2 Lamda^3)
with, using values from Al(OH)3, as example :
Re 2.82 E-15 m
Vc 425 E-30 m^3 Cell volume
Lambda 1.54 E-10 m Wavelength
RSlit 0.029 deg = 5 E-4 rad Receiving slits (rad)
VDiv 2.3 deg = 4 E-2 rad Vertical divergency (rad)
Eff 1 Efficiency and air absorption
Mu (3x.43+48x11.5+27x48.6)/(3+48+27) x 2.4
57 cm^-1 = 5.7 E3 m^-1 Sample absorption
In this case we have No = 3.10 E12 Scale
xnd top Next file Previous file

JFB Feb 21th, 1997