XANES of the AuLIII Edge in gold metal and in two compounds AuCN and AuCl3

The X-ray Absorption Near Edge Structure (XANES) of the AuLIII edge in gold metal and in its two compounds AuCN and AuCl3 have been recorded. The observed chemical shifts of the edge and the fine structure peaks in the compounds are discussed. It is observed that the energy shifts Delta E of the AuLIII due to chemical effects in aurous cyanide (AuCN) and auric chloride (AuCl3) with respect to the pure Au edge is 2.9 eV in AuCN and 0.7eV in AuCl3. The edge widths in AuCN and AuCl3 are found to be almost the same for both the compounds, presumably because electronegativities of CN and Cl are not very different. The observed fine structure peaks of the discontinuities of AuCN and AuCl3 are displaced progressively away from the main edge.