TY - JOUR
T1 - Refining structures against reflection rank
T2 - An alternative metric for electron crystallography
AU - Eggeman, Alexander S.
AU - Midgley, Paul A.
PY - 2012/5
Y1 - 2012/5
N2 - A new metric is proposed to improve the fidelity of structures refined against precession electron diffraction data. The inherent dynamical nature of electron diffraction ensures that direct refinement of recorded intensities against structure-factor amplitudes can be prone to systematic errors. Here it is shown that the relative intensity of precessed reflections, their rank, can be used as an alternative metric for refinement. Experimental data from erbium pyrogermanate show that applying precession reduces the dynamical transfer of intensity between reflections and hence stabilizes their rank, enabling accurate and reliable structural refinements. This approach is then applied successfully to an unknown structure of an oxygen-deficient bismuth manganite resulting in a refined structural model that is similar to a calcium analogue.
AB - A new metric is proposed to improve the fidelity of structures refined against precession electron diffraction data. The inherent dynamical nature of electron diffraction ensures that direct refinement of recorded intensities against structure-factor amplitudes can be prone to systematic errors. Here it is shown that the relative intensity of precessed reflections, their rank, can be used as an alternative metric for refinement. Experimental data from erbium pyrogermanate show that applying precession reduces the dynamical transfer of intensity between reflections and hence stabilizes their rank, enabling accurate and reliable structural refinements. This approach is then applied successfully to an unknown structure of an oxygen-deficient bismuth manganite resulting in a refined structural model that is similar to a calcium analogue.
KW - precession electron diffraction
KW - structure refinement
UR - http://www.scopus.com/inward/record.url?scp=84860135797&partnerID=8YFLogxK
U2 - 10.1107/S0108767312007234
DO - 10.1107/S0108767312007234
M3 - Article
AN - SCOPUS:84860135797
SN - 0108-7673
VL - 68
SP - 352
EP - 358
JO - Acta Crystallographica Section A: Foundations of Crystallography
JF - Acta Crystallographica Section A: Foundations of Crystallography
IS - 3
ER -