Extreme Ultraviolet Reflection Spectroscopy of Lanthanides and Actinides Using a High Harmonic Generation Light...

Area of Science:

• Atomic and Molecular Physics
• Materials Science
• Spectroscopy

Background:

• Shallow-core d and f orbital spectroscopy in lanthanides and actinides provides crucial insights into electronic structure and bonding.
• Traditional spectroscopy in this energy range faces challenges due to limited light sources and shallow penetration depths.

Purpose of the Study:

• To develop and demonstrate a laboratory-scale extreme ultraviolet (XUV) absorption spectroscopy method for studying f-electron systems.
• To overcome the limitations of conventional spectroscopy for analyzing lanthanide and actinide compounds.

Main Methods:

• Utilized a tabletop, laser-driven, high harmonic generation (HHG) source producing ultrafast XUV pulses (40-140 eV).
• Performed reflection spectroscopy at N4,5 and O4,5 absorption edges on lanthanide and uranium oxide crystals.
• Employed density functional theory (DFT) calculations for spectral assignment and prediction.

Main Results:

• Successfully measured XUV reflection spectra at the N4,5 and O4,5 edges of lanthanide and uranium oxides.
• Assigned electronic transitions by comparing experimental data with DFT calculations.
• Demonstrated the capability to predict spectra for other lanthanides.

Conclusions:

• This work establishes XUV absorption spectroscopy as a viable laboratory technique for studying crystalline and molecular f-electron systems.
• The developed method has broad applications in surface chemistry, photochemistry, electronic structure determination, and nuclear forensics.