Valence-to-core-detected X-ray absorption spectroscopy: targeting ligand selectivity

Area of Science:

• Spectroscopy
• Materials Science
• Biochemistry

Background:

• X-ray absorption spectroscopy (XAS) provides insights into transition-metal active sites.
• Standard XAS averages contributions, limiting ligand selectivity.
• Valence-to-core (VtC) XES offers potential for enhanced spectral analysis.

Purpose of the Study:

• To investigate the enhancement of XAS features using VtC-detected XAS.
• To improve ligand selectivity in XAS analysis.
• To explore the application of VtC-detected XAS for transition-metal compounds.

Main Methods:

• Obtained VtC-detected XAS spectra by monitoring valence-to-core X-ray emission (VtC XES).
• Acquired data from Mn model compounds at different VtC emission energies.
• Collected standard total fluorescence yield (TFY) XAS and nonresonant XES data for comparison.

Main Results:

• VtC-detected XAS showed dramatic intensity variations and new pre-edge features.
• Distinct energetic shifts in VtC emission were observed for different ligands.
• Density functional theory (DFT) modeling reproduced standard XAS and XES but not VtC-RXES.

Conclusions:

• VtC-detected XAS significantly enhances spectral information and selectivity.
• The method shows potential for detailed analysis of transition-metal active sites.
• Further theoretical development is needed to fully interpret VtC-RXES data.