How to: Match and Optimise PXRD Patterns in Mercury

Описание: In this video you can find out how to compare Powder X-ray Diffraction patterns with the Powder Pattern simulator tool in Mercury. We demonstrate how to load a reference pattern and identify potential structure matches visually and by the similarity score. We also show how to optimise the simulated PXRD pattern to fit the reference data using the optimiser.

If you have no previous experience of the PXRD simulator in Mercury, you can find an introductory video here    • How to: use the Powder Pattern Simulator i...  

In this video:
-00:03 Introduction
-00:37 Selecting a structure
-00:55 Simulating the powder pattern
-01:41 Loading a reference (experimental) pattern and evaluating similarity
-03:15 Configuring a PXRD optimisation
-05:11 Running a PXRD optimisation and evaluating the results
-06:15 Customising the Powder Pattern display
-06:40 Saving the simulated and optimised patterns

If you have not applied a background correction to the reference data, you should do so before optimising the simulated pattern. If you do not have proprietary software available, you can try DASH https://github.com/ccdc-opensource/dash.

Please note that the availability of some PXRD simulation features depends on the type of CSD license that you have and that CSD-Software version 2025.3 or later is required.

CSD-Enterprise gives access to both match and optimise.
CSD-Core and industrial licences that include CSD-Core (such as CSD-Discovery, CSD-Materials) have access to match.
CSD-Materials and licences that include CSD-Materials (Research Partnership) have access to both match and optimise.

You can read more about optimising crystal structures with experimental PXRD data here https://www.ccdc.cam.ac.uk/discover/b... .

If you would like to explore using autoFIDEL via the CSD Python API, see the documentation here: https://downloads.ccdc.cam.ac.uk/docu...

References:
For the similarity score, the cross-correlation method is described in R. de Gelder, R. Wehrens and J. A. Hageman, J. Comput. Chem., 2001, 22, 273-289 (https://doi.org/10.1002/1096-987X(200....
The FIDEL method upon which Jonas Nyman’s autoFIDEL optimisation program is based is described in S. Habermehl, P. Mörschel, P. Eisenbrandt, S. M. Hammer and M. U. Schmidt, Acta Cryst., 2014, B70, 347-359 (https://doi.org/10.1107/S205252061303....

You can grow your skills with using Mercury for visualizing structures using the free CSDU module “Visualization 101 – Visualizing structural chemistry data with Mercury” here: https://www.ccdc.cam.ac.uk/community/...

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