Computational Fourier Transform Analysis of Liquid Krypton Neutron Diffraction Data

Moss, Benjamin

Abstract

The structure factor of a fluid and its radial distribution function are linked by a Fourier transform relationship. This is tested on raw structure factor data of liquid krypton at 310K with pressures ranges from 400bar to 2000bar from neutron scattering experiments that were provided by the supervisor of this project, John Proctor. Results from three variations of the Fourier transform methods are presented. These methods are the direct Fourier transform, the Lorch method and the Soper-Barney method. The Fourier transforms were calculated numerically using an Octave code that was heavily modified by myself from Proctor et al. (2023). These results were compared to simulations performed using the Dissolve software. It is found that Fourier transforming structure factor data using these methods results in an unphysical radial distribution function as the calculated results do not match that of Dissolve’s Reverse Monte Carlo of diffraction data. Attempts were made to correct this by smoothing the structure factor data, however although there is a significant change in the results, they are still unphysical. Nevertheless, some smoothing methods have provided a reduction in the many unphysical oscillations that occur.

• Thesis Type: Thesis
• Online Publication Date: Jun 19, 2025
• Deposit Date: Jun 11, 2025
• Publicly Available Date: Jul 20, 2025
• Award Date: Jun 19, 2025