Autocorrelation from X-ray Scattering Data

In this post we will provide the overall work flow to get the autocorrelation of the electron density from an X-ray Scattering Intensity plot.

Raw Image

Let’s start with the real image.

Symmetrize the Image

By taking the upper left quadrant of the data and titling it to the other 3 quadrants we get the image below.

Handling the Beam Stop

Because we need to have the intensity of the image at the locations where the beam is placed to protect the detector, the values at the center of the image need to be filled in. Below is a first order example of what need to be changed in the data to account for the beam intensity.

Take Inverse Fourier Transform

If we take the inverse Fourier transform of the symmetric image, we get the autocorrelation of the electron density.

Next Steps

1. Understand differences in SAXS and WAXS intensity plots
2. Understand contributions from local states
3. Determine how to handle beam stop portion of the image (iterate between autocorrelation and XRS intensity data?)