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Figure 5
Reliability of the WPDFM method. (a), (c), (e) The intensity profile from Pd crystals with f.c.c. structure (unit cell = 3.8907 Å). (b), (d), (f) Absolute intensity difference between the profiles simulated via the DSE and modeled using the WPDFM method. Although the goodness of fit (GoF) of the agreement between the Debye simulated and WPDFM modeled patterns was calculated in the Q range from 2.0 to 10.0 Å−1, the values calculated including the small-angle region (Q ≤ 2.0 Å−1) are shown in parentheses. (a), (b) The intensity profile from a 6 nm spherical Pd (f.c.c.) crystal with perfect structure. The Debye profile is solved for a single configuration with lattice origin at the center of the sphere (concentric), or as the average profile from 1000 equivalent models with a random displacement of the lattice origin. (c), (d) The intensity profile from a 22 nm cubic Pd (f.c.c.) crystal with perfect structure. The size that optimizes the agreement between Debye simulated and modeled profiles was estimated to be ∼21.98 nm. (e), (f) The intensity profile from a powder of Pd (f.c.c.) cubic crystals with a uniform size distribution from 5 to 14 nm. The anomalous noise at Q ≃ 1.614 Å−1 represents the step size of the crystal models that is the Pd unit-cell parameter.

Volume 8| Part 2| March 2021| Pages 257-269
ISSN: 2052-2525