Positional recurrence maps, a powerful tool to de-correlate static and dynamical disorder in distribution maps from molecular dynamics simulations: the case of Nd2NiO4+d

Abstract

In order to investigate the on-site motion of the diffusive species in crystalline solids, we have implemented a code to perform a time-summation of displacements of specific atoms, involving symmetry and adapted projections. The resulting 2D maps have been called ‘positional recurrence maps’ (PRM). Only displacements are considered, instead of positions, so static deformations are filtered out. In this paper we present the PRM method and show the type of information on the dynamics of selected atoms that can be obtained. We take, as an example, the Nd₂NiO_4+d system in which we were able to characterize in detail the effects of the dynamical delocalization of the apical oxygen.