Chemical speciation and electronic structure with X-ray Absorption Spectroscopy
Sigray’s QuantumLeap™ brings the long-awaited power of X-ray absorption spectroscopy (XAS), a synchroton technique for determining electronic structure of elements, to individual laboratories. With QuantumLeap, researchers will now be able to identify and quantify the chemical species of elements of interest.
What is XAS?
X-ray absorption spectroscopy (XAS) is a technique in which the x-ray energy is scanned in incremental steps near the specific absorption edge (binding energy) of an element of interest. At this energy, x-rays typically are absorbed by an electron that is then emitted from the atom. XAS is comprised of two regimes:
XANES and EXFAS
The near-edge XANES region contains features and shifts in the absorption peak values caused by the transition of
core electrons to non-bound levels, and is sensitive to local atomic states such as oxidation states.
Extended fine structure (EXAFS) above the edge are formed by the wave-like nature of the emitted photoelectron, which
is scattered by surrounding atoms and forms oscillations from constructive and destructive interference that can
be then used to infer bond lengths and information on neighboring atoms.