A noise-robust data assimilation method for crystal structure determination using powder diffraction intensity

S Yoshikawa and R Sato and R Akashi and S Todo and S Tsuneyuki, JOURNAL OF CHEMICAL PHYSICS, 157, 224112 (2022).

DOI: 10.1063/5.0125553

Crystal structure prediction for a given chemical composition has long been a challenge in condensed-matter science. We have recently shown that experimental powder x-ray diffraction (XRD) data are helpful in a crystal structure search using simulated annealing, even when they are insufficient for structure determination by themselves Tsujimoto et al., Phys. Rev. Mater. 2, 053801 (2018). In the method, the XRD data are assimilated into the simulation by adding a penalty function to the physical potential energy, where a crystallinity-type penalty function, defined by the difference between experimental and simulated diffraction angles was used. To improve the success rate and noise robustness, we introduce a correlation-coefficient-type penalty function adaptable to XRD data with significant experimental noise. We apply the new penalty function to SiO2 coesite and e-Zn(OH)(2) to determine its effectiveness in the data assimilation method.

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