A new approach to structure amplitude determination from 3-beam convergent beam electron diffraction patterns

Philip N H Nakashima; Alexander F Moodie; Joanne Etheridge

doi:10.1016/j.ultramic.2011.01.044

A new approach to structure amplitude determination from 3-beam convergent beam electron diffraction patterns

Ultramicroscopy. 2011 Jun;111(7):841-6. doi: 10.1016/j.ultramic.2011.01.044. Epub 2011 Feb 4.

Authors

Philip N H Nakashima¹, Alexander F Moodie, Joanne Etheridge

Affiliation

¹ ARC Centre of Excellence for Design in Light Metals, Monash University, Victoria 3800, Australia. Philip.Nakashima@monash.edu

PMID: 21664549
DOI: 10.1016/j.ultramic.2011.01.044

Abstract

The intensity distribution in three-beam CBED patterns from centrosymmetric crystals can be inverted analytically to enable the direct measurement of crystal structure amplitudes and three-phase invariants. The accuracy of the measurements depends upon the accuracy and precision with which specific loci within the discs can be identified. The present work exploits the equivalence in form of the intensity distribution along these loci to provide an algorithm for their automated location, enabling the rapid and unequivocal identification of their position. Moreover, it demonstrates how the loci can be used to determine directly the relative magnitudes of structure amplitudes with superior accuracy and without recourse to complex pattern-matching calculations.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Algorithms
Crystallography / methods*
Electrons*
Microscopy, Electron, Transmission / methods*