XANES analysis

What is  XANES analysis used for?

XANES has a variety of applications in fields including nanomaterial and thin film characterization, chemical engineering, and environmental analysis:

• Characterization of surface and sub-surface elements in thin film samples.

• Assays in environmental science and geochemistry, such as of rock, soil, and water samples.

• Obtaining information on the qualitative elemental composition of unknown samples.

• Determining coordination chemistry of inorganic and organometallic compounds.

• Gathering information about metal coordination centers in biomolecules.

• Determining the mechanisms and monitoring the effectiveness of heterogeneous catalysts.

How does XANES work?

XANES employs a tunable X-ray source to probe the sample, exciting core electrons from deep atomic levels to higher energy states. By measuring absorption at varying X-ray energies, one can identify specific absorption edges where significant variations in X-ray absorption occur. These 'fingerprint' absorption edges are characteristic of the sample's elemental composition and provide insight into the bonding environment, coordination chemistry, and oxidation states of the elements present. 

XANES and EXAFS

Extended X-ray absorption fine structure (EXAFS) is a technique complementary to XANES, together covering the full range of X-ray absorption spectroscopy (XAS). While XANES analyzes structures (signal patterns) near the absorption edge, EXAFS examines the fine structure beyond the edge. It exploits the interference patterns in absorption spectra caused by the backscattering of photo-ejected electrons from surrounding atoms to give insights into the local structural environment, including inter-atomic distances and neighbor identities. Used in tandem, EXAFS and XANES offer a comprehensive picture of both the electronic structure and atomic arrangement in materials.

Sample preparation

Achieving a suitable sample thickness is crucial for XANES; typically, a few tens of nanometers to a few micrometers are optimal, ensuring sufficient X-ray interaction without excessive absorption. The thickness range varies significantly depending on the material.

Advantages and limitations of XANES analysis

The main strength of XANES is that the information it provides is very specific to elements and their oxidation states. This can help to identify elements that may not appear in other spectroscopic analyses, such as EPR. XANES is typically non-destructive, however, it should be noted that certain sample types can be sensitive to X-ray radiation and therefore it can be partially destructive in these cases.

XANES analysis can be conducted in a laboratory, or at a large-scale research facility that makes use of a synchrotron X-ray source. While synchrotron facilities are powerful X-ray sources, access to such facilities often comes at a greater time and financial cost, and for this reason, laboratory-scale XANES is better suited for routine testing, or when utmost detection efficiency is not required.

Need an analysis?

Measurlabs offers laboratory testing services with XANES and other advanced materials science techniques for researchers and industry customers. Due to our large global network of partner laboratories, we can offer a range of difficult-to-source techniques, such as ToF-ERDA, TXRF, SAXS, WAXS, and micro-CT, all in one place. Do not hesitate to contact our experts through the form below to learn more and to request a quote for your samples.