Refinement of X‐ray and electron diffraction crystal structures using analytical Fourier transforms of Slater‐type atomic wavefunctions in Olex2

Kleemiss, Florian; Peyerimhoff, Norbert; Bodensteiner, Michael

Abstract

An implementation of Slater‐type spherical scattering factors for X‐ray and electron diffraction for elements in the range Z = 1–103 is presented within the software Olex2. Both high‐ and low‐angle Fourier behaviour of atomic electron density and electrostatic potential can thus be addressed, in contrast to the limited flexibility of the four Gaussian plus constant descriptions which are currently the most widely used method for calculating atomic scattering factors during refinement. The implementation presented here accommodates the increasing complexity of the electronic structure of heavier elements by using complete atomic wavefunctions without any interpolation between precalculated tables or intermediate fitting functions. Atomic wavefunctions for singly charged ions are implemented and made accessible, and these show drastic changes in electron diffraction scattering factors compared with the neutral atom. A comparison between the two different spherical models of neutral atoms is presented as an example for four different kinds of X‐ray and two electron diffraction structures, and comparisons of refinement results using the existing diffraction data are discussed. A systematic but slight improvement in R values and residual densities can be observed when using the new scattering factors, and this is discussed relative to effects on the atomic displacement parameters and atomic positions, which are prominent near the heavier elements in a structure.

Citation

Kleemiss, F., Peyerimhoff, N., & Bodensteiner, M. (2024). Refinement of X‐ray and electron diffraction crystal structures using analytical Fourier transforms of Slater‐type atomic wavefunctions in Olex2. Journal of Applied Crystallography, 57, 161-174. https://doi.org/10.1107/s1600576723010981

• Journal Article Type: Article
• Acceptance Date: Dec 21, 2023
• Online Publication Date: Jan 26, 2024
• Publication Date: Jan 26, 2024
• Deposit Date: Feb 2, 2024
• Publicly Available Date: Feb 2, 2024
• Journal: Journal of Applied Crystallography
• Print ISSN: 0021-8898
• Electronic ISSN: 1600-5767
• Publisher: International Union of Crystallography
• Peer Reviewed: Peer Reviewed
• Volume: 57
• Pages: 161-174
• DOI: https://doi.org/10.1107/s1600576723010981
• Keywords: electron diffraction, X‐ray diffraction, refinement
• Public URL: https://durham-repository.worktribe.com/output/2174540