diffpy.morph

Diffpy.morph is a Python software package designed to allow researchers the ability to compare experimental datasets to identify structural changes.

Diffpy.morph makes use of several data manipulation techniques to correct for benign effects such as thermal expansion (peak shift) and increased thermal motion (peak broadening) or a change in scale due to differences in incident flux, for example. diffpy.morph will do its best to correct for these benign effects before computing and plotting a difference curve.

One dataset is designated as the “target”, while the second is morphed. Such morphs include stretching (modifying the x-axis to simulate uniform expansion), smearing (broadening peaks via uniform convolution), and scaling. In addition to these operations, diffpy.morph offers other morphing transformations, though stretching, smearing, and scaling are the most commonly used. The software automatically varies the amplitudes of the selected transformations to obtain the best fit between the morphed and target datasets, and then plots both datasets along with the resulting difference curve shown below.

Note that diffpy.morph works on other spectra, not just pair distribution functions (PDFs).

diffpy.morph transformation techniques applied to PDFs of IrTe₂ doped with different atomic species at different temperatures. The left column (a, b, and c) shows the unmorphed PDFs at 10K (blue) and 300K (red) and their corresponding difference curves. The right column (d, e, and f) shows the same PDFs after applying the stretch, smear, and scale transformations to the 10K PDFs. No phase transition is observed for PDFs in d and e as the difference curves are flat (low R_w). However, a large difference curve (high R_w) is observed in f, signifying a structural phase transition between 10K and 300K.

Installation

For the most up-to-date installation instructions, please refer to the installation section of the diffpy.morph README page on GitHub.

Tutorials

Tutorials on how to use diffpy.morph can be found at the diffpy.morph documentation.

Documentation

Documentation for diffpy.morph is available at https://www.diffpy.org/diffpy.morph.