Ligand-metal bonding effects in resonance enhanced x-ray Bragg diffraction
S W Lovesey1,2, G van der Laan2
1ISIS Facility, STFC, Didcot, Oxfordshire OX11 0QX, United Kingdom.
Summary
This study explores chlorine K-edge resonant x-ray Bragg diffraction for analyzing materials like K2CuCl3 and K2RuCl6. The technique reveals insights into chlorine-metal bonds and structural chirality in novel materials.
Area of Science:
- Materials Science
- Solid-State Physics
- Crystallography
Background:
- Many functional materials feature chlorine covalently bonded to open-shell metals.
- These materials exhibit diverse properties, including luminescence and magneto-chiral effects.
- Examples include K2CuCl3, Rb2CuCl3, CsCuCl3, and K2RuCl6.
Purpose of the Study:
- To investigate the utility of chlorine K-edge resonant x-ray Bragg diffraction.
- To analyze chlorine multipoles and their contribution to diffraction patterns.
- To explore benefits for characterizing structural chirality and bonding in metal chlorides.
Main Methods:
- Symmetry-informed calculations of chlorine multipoles.
- Analysis of x-ray absorption spectra (XAS) at the chlorine K-edge.
- Detailed treatment of Bragg diffraction from chlorine in K2RuCl6.
- Examination of diffraction patterns in rhombohedral compounds.
Main Results:
- A low-energy feature in XAS spectra is linked to the chlorine-metal bond.
- Resonant x-ray Bragg diffraction confirms structural chirality in CsCuCl3.
- Diffraction patterns for rhombohedral compounds with forbidden Bragg spots are simplified.
- Singlet ground state in K2RuCl6 arises from antiparallel spin and orbital angular momenta.
Conclusions:
- Chlorine K-edge resonant x-ray Bragg diffraction is a valuable tool for materials characterization.
- The technique provides insights into electronic structure and bonding.
- It offers a method for studying chiral materials and complex magnetic structures.
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