Soft X-ray Absorption Spectroscopy

X-ray absorption near edge structure (XANES) or near edge X-ray absorption fine structure (NEXAFS) is powerful tool to investigate inner shell excitation of an atom or molecule. The photon-energy tunability of synchrotron radiation is essential for probing these core levels. Unlike the hard X-ray absorption measurements, the samples are measured under ultra-high vacuum conditions which are required for this photon energy range. One of the examples of this technique is determination of molecule orientation in organic compounds. Orientational ordering of molecules can be determined by carbon NEXAFS spectra with help of the linear polarization nature of synchrotron radiation.

Each element has its own set of core levels that occur at characteristic energies. The photon-energy tunability of synchrotron radiation is essential for probing these core levels.  For examples, absorption of transition metals (L-edges), oxygen (K-edge), nitrogen (K-edge), and carbon (K-edge) can be investigated. A total-electron-yield method is used for soft x-ray absorption spectroscopy measurements.

 

Beamlines

Variable Line-Spaced Plane Grating Monochromator, VLSPGM

180-900 eV, SR-based XPS, total/partial yield

 

5m Toroidal Grating Monochromator, 5m-TGM

25-240 eV, photoemission, UPS, XPS, LEED, film growth

 

Contact

Research/Technical Lead: Orhan Kizilkaya