Key applications of XAS include materials science, chemical and biochemical research, often for the identification of metals in a sample (e.g. metals, nanoparticles, or in the active sites of metalloproteins/metalloenzymes) and their oxidation states.
In TEM/Scanning TEM (STEM) high energy electrons incident on ultra-thin samples, allow imaging, diffraction, electron energy loss spectroscopy and chemical analysis of solid materials with a spatial resolution on the order of 1-2 Å. Samples must have a thickness of a few tens of nanometres and are prepared in sample preparation laboratory.
ICP-MS allows measuring elements at trace levels. Dissolved sample is introduced into an argon plasma where the molecules are dissociates and further ionized. Singly-charged ions thus formed are directed into the mass spectrometer. A special application of ICP-MS (spICP-MS) allows measuring size and number concentration of a particle suspension.
XRD provides non-destructive information on the structural order of a material. At large scattering angles XRD permits to identify different crystal phases and to quantify lattice distances and crystalline volume fractions. At low angles of incidence the surface roughness of a single crystal and the thickness of a deposition layer can be obtained.
XAS is sensitive to the local bonding environment of the atom absorbing the X-rays, providing information on oxidation states, local orbital symmetry, molecular orientation and chemically selective density of states. It is widely used in molecular and condensed matter physics, material science, engineering, chemistry, earth science and biology.
This technique offers the possibility of performing molecular dynamics at finite temperature via DFT calculations as well as empirical potentials, modeling temperature activated processes (NEB and metadynamics), simulating complex environments via QM/MM and implicit solvation models.