Polycrystalline diffraction patterns may be hard to decrypt without some visualization tools. This tutorial goes over some of the tools available in scikit-ued that help solve this problem.
Patterson pair-pair distribution function¶
The calculation of the Patterson pair-pair distribution requires knowledge of the investigated material. You must also determine what range of real-space radii over which you want to calculate the distribution.
As an example, let’s use a simulated diffraction pattern of monoclinic VO$_2$:
>>> import numpy as np >>> import matplotlib.pyplot as plt >>> from crystals import Crystal >>> from skued import patterson, powdersim >>> >>> # Simulation of polycrystalline diffraction pattern >>> # for monoclinic VO2 >>> cryst = Crystal.from_database('vo2-m1') >>> q = np.linspace(0.2, 10, 1024) >>> I = powdersim(cryst, q) >>> >>> # Determination of the pair-pair distribution function >>> rr = np.linspace(1, 5, 256) >>> pairdist = patterson(q = q, I = I, crystal = cryst, radii = rr) >>> >>> fig, ax = plt.subplots(1,1) >>> ax.plot(rr, pairdist, '.k')