Modelling dynamical 3D electron diffraction intensities. I. A scattering cluster algorithm

Mendis, Budhika

Abstract

Three‐dimensional electron diffraction (3D‐ED) is a powerful technique for crystallographic characterization of nanometre‐sized crystals that are too small for X‐ray diffraction. For accurate crystal structure refinement, however, it is important that the Bragg diffracted intensities are treated dynamically. Bloch wave simulations are often used in 3D‐ED, but can be computationally expensive for large unit cell crystals due to the large number of diffracted beams. Proposed here is an alternative method, the `scattering cluster algorithm' (SCA), that replaces the eigen‐decomposition operation in Bloch waves with a simpler matrix multiplication. The underlying principle of SCA is that the intensity of a given Bragg reflection is largely determined by intensity transfer (i.e. `scattering') from a cluster of neighbouring diffracted beams. However, the penalty for using matrix multiplication is that the sample must be divided into a series of thin slices and the diffracted beams calculated iteratively, similar to the multislice approach. Therefore, SCA is more suitable for thin specimens. The accuracy and speed of SCA are demonstrated on tri‐isopropyl silane (TIPS) pentacene and rubrene, two exemplar organic materials with large unit cells.

Citation

Mendis, B. (2024). Modelling dynamical 3D electron diffraction intensities. I. A scattering cluster algorithm. Acta Crystallographica Section A: Foundations and Advances, 80(2), 167-177. https://doi.org/10.1107/s2053273323010689

• Journal Article Type: Article
• Acceptance Date: Dec 13, 2023
• Online Publication Date: Jan 25, 2024
• Publication Date: 2024-03
• Deposit Date: Feb 28, 2024
• Publicly Available Date: Feb 28, 2024
• Journal: Acta Crystallographica Section A
• Print ISSN: 2053-2733
• Electronic ISSN: 2053-2733
• Publisher: International Union of Crystallography
• Peer Reviewed: Peer Reviewed
• Volume: 80
• Issue: 2
• Pages: 167-177
• DOI: https://doi.org/10.1107/s2053273323010689
• Public URL: https://durham-repository.worktribe.com/output/2174545