Improving Resolution in k and r Space: A FEFF-based Wavelet for EXAFS Data Analysis

Applying a wavelet analysis based on the Morlet mother function, we previously demonstrated the presence of both Al and Zn atoms in the first metal shell (r ≈ 3 Å from the central Zn atom) of Zn-Al layered double hydroxide (LDH). However, this approach was not suited to resolve the second and third metal shells (r ≈ 5 6 Å) in r and k space independently. Therefore, we developed a new FEFF-Morlet wavelet, where the EXAFS function itself, extracted from the FEFF model, is combined with the complex Morlet wavelet. With this method, we were able to distinguish the second metal shell (Zn atoms only) from the third metal shell (Zn and Al atoms), thereby proving a regular, dioctahedral distribution of Zn atoms in the hydroxide layers.