Measuring the Electronic State of Individual Metal Atoms

At the upcoming American Chemical Society (ACS) Fall 2026 Meeting, there will be a talk on structural chemistry that spectroscopists might find insightful. On Monday August 24^th at 12:10 pm EDT, Neal Mankad, who is a professor at the University of Illinois – Chicago, will deliver a talk titled, “Spatial Mapping of Electronic Structure in Molecular Copper Clusters Using Resonant X-ray Diffraction.”¹ In his presentation, Mankad will present a technique that can measure the electronic state of individual metal atoms within multinuclear clusters, addressing a longstanding gap in structural chemistry.¹

What will the presentation cover?

In his presentation, Mankad will talk about the latest research his laboratory is conducting on structural chemistry. His presentation will describe how his group has applied diffraction anomalous fine structure (DAFS) to a series of molecular copper clusters ranging from two to eight metal centers.¹ Mankad will review how the method his team developed solves a problem that has limited researchers' understanding of metal clusters for decades: conventional X-ray absorption spectroscopy (XAS), the standard tool for determining a metal's oxidation state, can only report an average value across all metal sites in a cluster, obscuring how electronic character is actually distributed among individual atoms.¹

To understand why this talk is significant, it’s important to know how DAFS works. DAFS pairs single-crystal X-ray diffraction with a dense sweep of X-ray wavelengths near the copper K-edge.¹ At each wavelength, the method refines anomalous scattering factors for every crystallographically distinct metal site in the structure.¹ Tracking how those scattering factors shift with energy yields a resonant absorption energy for each site individually, effectively combining the site-resolution of diffraction with the electronic sensitivity of absorption spectroscopy.¹

Mankad's presentation will cover benchmarking work on simpler di-, tri-, and tetranuclear copper clusters. The goal of the talk is to establish that DAFS results align with expectations from known structures.¹ The talk will then turn to more complex hexa-, hepta-, and octanuclear copper hydride clusters, where site-specific oxidation-state data have not previously been available.¹

The clusters that Mankad’s group studied serve as molecular models for copper nanomaterials, which are used in catalysis, electronics, and energy applications. Because bulk nanomaterials are difficult to characterize atom-by-atom, well-defined molecular clusters offer a route to test fundamental principles of electronic structure that can then inform understanding of larger, less tractable systems.¹

For chemists working on cluster synthesis, catalysis, or nanomaterial design, the significance lies in the availability of a new experimental benchmark: DAFS provides site-resolved data that computational models have often had to predict without direct verification.¹ Establishing reliable experimental ground truth for how charge and oxidation state distribute across metal centers could refine theoretical frameworks used across the field of cluster chemistry, particularly for systems where uniform oxidation states cannot be assumed.¹

What is the American Chemical Society Fall 2026 Meeting?

The ACS Fall 2026 Meeting is a scientific conference dedicated to chemistry and related disciplines.The conference brings together thousands of academic researchers, industry scientists, government laboratory researchers, undergraduate and graduate students, instrument manufacturers, and science educators and policymakers under one roof.²

The meeting typically features several events for attendees. These events include oral and poster presentations, plenary lectures, technical symposia, professional development workshops, career fairs and networking events, and an exposition where companies showcase their latest instruments and products.²

Why is this meeting important for spectroscopists?

For the spectroscopy community, the ACS Fall Meeting is an important venue for learning about advances in techniques such as Raman spectroscopy, infrared (IR) spectroscopy, nuclear magnetic resonance (NMR), mass spectrometry (MS), laser-induced breakdown spectroscopy (LIBS), X-ray methods, chemometrics, hyperspectral imaging (HSI), and other analytical technologies.^1,2

For more information about the upcoming conference, you can visit the ACS website.

References

1. Mankad, N. Spatial Mapping of Electronic Structure in Molecular Copper Clusters Using Resonant X-ray Diffraction. Presented at the American Chemical Society Fall 2026 Meeting, Chicago, Illinois, August 24, 2026. Available at: https://acs.digitellinc.com/live/37/page/1374?search=spectroscopy&tags=475&page=55&window-jn2mj2&window-w33qsi&window-svv07a
2. Wetzel, W. Why Spectroscopists Should Attend the ACS Fall 2026 Conference. Spectroscopy Online, 2026. https://www.spectroscopyonline.com/view/why-spectroscopists-should-attend-the-acs-fall-2026-conference (accessed July 14, 2026).