X-ray Absorption Near Edge Structures at the L_(3,2) and M_(3,2) edges: a Probe for the Electronic Behavior of Metal Nanostructures

摘要

We present a comparison of the calculation and experiment results of the X-ray Absorption Near Edge Structures (XANES) of the L_(3,2)-edges and the M_(3,2) -edges of representative 5d metals. Emphasis is placed on the first 10 -15 eV above the Fermi level where the behavior of the relatively localized unoccupied d densities of states of transition metals across the periodic table can be probed. Experimentally, this is where the whiteline appears. The whiteline intensity contains information about the d holes at the metal site. We adopt a method of the Full Potential Linearized Augmented Plane Wave (FPLAPW) based on the Density Functional Theory with the modification of the exchange-correlation energy by Generalized Gradient Approximation (The Wien computer code). The calculation of electronic structure is performed starting by either compressing or expanding the lattices, to minic nano-structural behavior. The results and their implications will be discussed.