X-ray absorption spectroscopy (XAS)
From Online Dictionary of Crystallography
Spectrométrie d'absorption des rayons X (Fr); Röntgenabsorptionsspektroskopie (Ge); Spettroscopia XAS (It); X線吸収分光法 (Ja).
X-ray Absorption Spectroscopy (XAS) is a technique for measuring the linear absorption coefficient µ(E) of a substance as a function of the incident photon energy E in the X-ray regime. This technique is element and orbital-specific and determines the local atomic and electronic structure of matter. XAS conventionally includes techniques of XAFS (q.v.), which in turn includes both XANES and EXAFS (q.v.). An XAS spectrum may also be obtained using fluorescence, electron yield and scattering processes indirectly (i.e. without directly measuring the absorption of X-rays).