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Figure 8
The real-space phases of a parabolic reconstruction of the PtIr specimen. (a) The phase-colored amplitude map (top) of the reconstruction shows a clustering of the phases in one quadrant of the polar plot (bottom; also called the complex plane or Argand diagram). The arrow shows that the real-space average phase shift is the sum of π/2 (90°) and the constant phase shift in the CTF of 0.38 (∼22°) used for the Pt amplitude contrast. Inset: phase colors corresponding to the polar plot. (b) Filtering out the zero frequency results a better interpretable representation (top) and in a clustering around the origin of the polar plot (bottom). (c) Filtering to retain frequencies between 1 and 3 Å gives structural features of the PtIr nanocrystals (top), with the phases peaking close to the real axis in the polar plot (bottom). Scale bar: 5 Å.

IUCrJ
Volume 13| Part 1| January 2026| Pages 77-93
ISSN: 2052-2525
https://doi.org/10.1107/S2052252525010796