High Energy Resolution Fluorescence Detection of the Pt L<sub>3,2</sub>-Edge Whitelines of Pt-Based Bimetallic Systems: Implications for the Pt 5d<sub>5/2,3/2</sub> Density of States
Jiatang Chen, Y. Zou Finfrock, Zhiqiang Wang, Tsun‐Kong Sham
Abstract
This study utilizes the state-of-the-art high energy resolution fluorescence detection (HERFD) and X-ray absorption fine-structure spectroscopy (XAFS) to revisit the Pt L3- and L2-edge whitelines (WLs) for Pt metal and to explore the Pt L3,2-edge WL–5d5/2,3/2 density of states (DOS) relationship for multiple Pt-Ni and Pt-Cu bimetallic fcc systems. A generalized linear correlation of the WL area with the unoccupied 5d states has been established. The unoccupied Pt 5d5/2 and 5d3/2 state counts are found to be correlated linearly despite the diversity of the systems under investigation. This finding allows for a straightforward and effective way to obtain the number of unoccupied Pt 5d states by only measuring the Pt L3-edge in these or similar systems. This observation also introduces a new spin on the Pt L3,2-edge WL intensity anomaly in that the Pt 5d3/2 states are not as full as previously thought. Guidance for the XAFS experiment design and charge redistribution implications using this correlation are discussed.