radial distribution function

A diffraction pattern (halo pattern) is taken from an isotropic amorphous substance. From the intensity distribution curve of the pattern, the smooth background passing through the center of the wavy curve is subtracted to remove only the interference term between different atoms. The "radial distribution function" is obtained by the Fourier transform of the interference term. The average interatomic distance (or the distribution of the interatomic distance), the coordination number and the density of the substance can be examined from the function.