Sub-second pair distribution function using a broad bandwidth monochromator

Nicolas P L Magnard; Daniel R Sørensen; Innokenty Kantor; Kirsten M Ø Jensen; Mads R V Jørgensen

doi:10.1107/S1600576723004016

Sub-second pair distribution function using a broad bandwidth monochromator

J Appl Crystallogr. 2023 May 31;56(Pt 3):825-833. doi: 10.1107/S1600576723004016. eCollection 2023 Jun 1.

Authors

Nicolas P L Magnard¹, Daniel R Sørensen^{2

3}, Innokenty Kantor^{3

4}, Kirsten M Ø Jensen¹, Mads R V Jørgensen^{2

3}

Affiliations

¹ Department of Chemistry and Nano-Science Center, University of Copenhagen, Copenhagen 2100, Denmark.
² Department of Chemistry & iNANO, Aarhus University, Aarhus 8000, Denmark.
³ MAX IV Laboratory, Lund University, Lund 224 84, Sweden.
⁴ Department of Physics, Technical University of Denmark, Lyngby 2880, Denmark.

Abstract

Here the use of a broad energy bandwidth monochromator, i.e. a pair of B₄C/W multilayer mirrors (MLMs), is demonstrated for X-ray total scattering (TS) measurements and pair distribution function (PDF) analysis. Data are collected both on powder samples and from metal oxo clusters in aqueous solution at various concentrations. A comparison between the MLM PDFs and those obtained using a standard Si(111) double-crystal monochromator shows that the measurements yield MLM PDFs of high quality which are suitable for structure refinement. Moreover, the effects of time resolution and concentration on the quality of the resulting PDFs of the metal oxo clusters are investigated. PDFs of heptamolybdate clusters and tungsten α-Keggin clusters from X-ray TS data were obtained with a time resolution down to 3 ms and still showed a similar level of Fourier ripples to PDFs obtained from 1 s measurements. This type of measurement could thus open up faster time-resolved TS and PDF studies.

Keywords: metal oxo clusters; pair distribution function; synchrotron radiation; total scattering.

Grants and funding

This work is funded by the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Programme (grant agreement No. 804066); the Villum Foundation through a Villum Young Investigator grant (grant No. VKR00015416); the Danish Ministry of Higher Education and Science through the SMART Lighthouse; and the Danish Agency for Science, Technology and Innovation, which funded the instrument center DanScatt (grant No. 7129-00006B). Research conducted at MAX IV is supported by the Swedish Research Council (contract No. 2018–07152), the Swedish Governmental Agency for Innovation Systems (contract No. 2018–04969) and Formas (contract No. 2019–02496). DanMAX is funded by the NUFI (grant No. 4059-00009B).