AN XANES STUDY OF CARBIDES OF MOLYBDENUM AND TUNGSTEN

The X-ray absorption near edge structure (XANES) of molybdenum and tungsten compounds has been studied by using synchrotron radiation. Substantial difference in XANES features between metals and their carbides suggested significant difference in electronic structure between them. The shift in edge position indicated charge transfer from metal to carbon when a carbide is formed. In light of a modern band theory, the larger white line areas for carbides could be interpreted as due to some of the unoccupied d-states which are not measured by x-ray white line areaclose2