Local structure correlations in plastic cyclohexane - a Reverse Monte Carlo study

TL;DR

This study uses Reverse Monte Carlo refinement of neutron scattering data to analyze local structural correlations in cyclohexane's solid phases, revealing that phase I's distortions resemble phase II's ordered structure.

Contribution

It introduces a data-driven approach to model instantaneous local structures in plastic solids, linking disordered and ordered phases of cyclohexane.

Findings

Instantaneous distortions in phase I resemble phase II's structure.

Local structure analysis reveals correlations between disordered and ordered phases.

Reverse Monte Carlo effectively models local configurations from neutron scattering data.

Abstract

Two solid phases of cyclohexane have been investigated over a temperature range spanning 13 to 266 K on a powdered, perdeuterated sample using neutron total scattering. Phase II has an ordered structure (C2/c) that forms below 186 K. Between 186 and 280 K it exists as a plastic solid - phase I (Fm3m), where the molecules are rotationally disordered about the lattice points of the face-centred cubic cell. Data-dependent atomistic configurations that represent the 'instantaneous' crystal structure have been generated from the total scattering data using Reverse Monte Carlo refinement. Analysis of local structure reveals that instantaneous distortions in phase I resemble the average structure of phase II.