X-rayK-absorption edge interpretation and energy determination

The low energy features of XANES (X-ray absorption near edge structure) in the X-rayK-absorption edge of transition metal systems have long been detected and attempts have been made to explain their origin. Only recently have some theoretical approaches based upon multiple scattering (MS) effects been applied in explaining the shape of theK-edge features. But the pre-edge shoulder, often labelled asB, has hitherto defied satisfactory explanation for its origin. The present work is an attempt in explaining the possible origin of this feature by using MS-theory to theK-edge XANES of some first row transition metal systems. The calculated energies using MS-formalism were found to be closer to the experimentally observed values for some systems of cobalt and copper. Using these results, theK-edge featuresA,B,C have been assigned to be originating from the resonance effects of scattering of the ejected photo-electron with the molecular potential set up by the central absorbing atom and its near neighbours.