EXAFS study of hydrogen intercalation into ReO3 using the evolutionary algorithm

In this study we have investigated the influence of hydrogen intercalation on the local atomic structure of rhenium trioxide using a new approach to EXAFS data analysis, based on the evolutionary algorithm (EA). The proposed EA-EXAFS method is an extension of the conventional reverse Monte Carlo approach but is computationally more efficient. It allows one to perform accurate analysis of EXAFS data from distant coordination shells, taking into account both multiple-scattering and disorder (thermal and static) effects. The power of the EA-EXAFS method is first demonstrated on an example of the model system, pure ReO₃, and then it is applied to an in situ study of hydrogen bronze H_xReO₃ upon hydrogen intercalation. The obtained results allow us to detect changes in the lattice dynamics and correlation of atomic motion, and to follow the structural development at different stages of the reaction.