Revealing charge anisotropies in metal compounds via high-purity x-ray polarimetry

TL;DR

This paper introduces a high-purity x-ray polarimetry method to analyze electronic anisotropies and charge distributions in metal compounds, revealing phase transition dynamics with high selectivity.

Contribution

It presents a novel polarization analysis technique using nuclear resonant x-ray scattering to study electronic structure changes during phase transitions in metal complexes.

Findings

Determined electric field gradients in iron(II) compounds during phase transition.

Monitored defect concentrations of electronic valence states across phase changes.

Enabled tracing of electronic and structural dynamics in metal compounds.

Abstract

Linear polarization analysis of hard x-rays is employed to probe electronic anisotropies in metal-containing complexes with very high selectivity. We use the pronounced linear dichroism of nuclear resonant x-ray scattering to determine electric field gradients in an iron(II) containing compound as they evolve during a temperature-dependent high-spin/low-spin phase transition. This method constitutes a novel approach to analyze changes in the electronic structure of metal-containing molecules as function of external parameters or stimuli. The polarization selectivity of the technique allows us to monitor defect concentrations of electronic valence states across phase transitions. This opens new avenues to trace electronic changes and their precursors that are connected to structural and electronic dynamics in the class of metal compounds ranging from simple molecular solids to biological molecules.