Official Resources
- Source Repository: https://github.com/kul-group/QuantEXAFS
- Documentation: Included in repository
- License: Open source
Overview
QuantEXAFS is a Python-based toolkit for automated fitting of Extended X-ray Absorption Fine Structure (EXAFS) data using X-ray Larch modules. It combines DFT-optimized structure databases with automated EXAFS fitting workflows, enabling quantitative structural analysis from EXAFS measurements.
Scientific domain: EXAFS analysis, X-ray absorption spectroscopy, structural fitting
Target user community: Researchers performing quantitative EXAFS analysis with DFT structural models
Theoretical Methods
- EXAFS theory (scattering formalism)
- FEFF scattering path calculation
- DFT structure optimization
- Nonlinear least-squares fitting
- Artemis/Larch fitting engine
- Multiple scattering paths
Capabilities (CRITICAL)
- Automated EXAFS fitting
- DFT structure database integration
- Multiple scattering path analysis
- Fitting of coordination numbers
- Fitting of Debye-Waller factors
- Fitting of bond distances
- Batch fitting of multiple spectra
- ASE database format support
Sources: GitHub repository
Key Strengths
Automated Workflow:
- No manual fitting steps
- Reproducible results
- Batch processing
- Systematic parameter exploration
DFT Integration:
- DFT-optimized structures as starting models
- ASE database format
- Consistent structure-spectra workflow
- High-quality structural models
Larch Integration:
- Uses mature XAS analysis library
- Well-tested fitting algorithms
- Standard EXAFS methodology
- Community-validated
Inputs & Outputs
-
Input formats:
- EXAFS data files
- ASE database of DFT structures
- FEFF calculation results
- Fitting parameter files
-
Output data types:
- Fitted structural parameters
- Fitted EXAFS spectra
- Residuals and R-factors
- Coordination numbers
- Bond distances and disorder
Interfaces & Ecosystem
- Larch: XAS analysis library
- ASE: Structure database management
- FEFF: Scattering path calculation
- DFT codes: Structure optimization (VASP, QE, etc.)
Performance Characteristics
- Speed: Fast (fitting is seconds, FEFF is minutes)
- Accuracy: Depends on model quality
- System size: Any size (EXAFS is local probe)
- Memory: Low
Computational Cost
- Fitting: Seconds per spectrum
- FEFF paths: Minutes per absorber
- DFT structures: Hours (pre-requisite)
- Typical: Very efficient fitting step
Limitations & Known Constraints
- EXAFS only: No XANES fitting
- Larch dependency: Requires Larch installation
- DFT pre-requisite: Need DFT-optimized structures
- Documentation: Limited
- Local structure only: EXAFS probes local environment
Comparison with Other Codes
- vs Demeter/Athena: QuantEXAFS adds DFT database integration
- vs Larch: QuantEXAFS automates fitting workflow
- vs FEFF: QuantEXAFS uses FEFF for paths, adds fitting
- Unique strength: Automated EXAFS fitting with DFT structure database integration
Application Areas
Nanoparticle Structure:
- Size-dependent structure
- Surface vs bulk coordination
- Shape determination
- Ligand effects
Amorphous Materials:
- Short-range order
- Bond distance distributions
- Coordination number analysis
- Structural modeling
Catalysis:
- Active site structure
- Under operating conditions
- Catalyst degradation
- Support effects
Battery Materials:
- Local structure changes
- Phase transitions
- Cation disorder
- Redox processes
Best Practices
DFT Structures:
- Use well-converged geometries
- Include relevant structural models
- Consider disorder and defects
- Validate against known structures
EXAFS Fitting:
- Use appropriate k-range
- Include sufficient R-range
- Test fitting stability
- Report uncertainties
Community and Support
- Open source on GitHub
- Developed at KU Leuven
- Research code
- Limited documentation
Verification & Sources
Primary sources:
- GitHub repository: https://github.com/kul-group/QuantEXAFS
- Related publications from KU Leuven
Confidence: VERIFIED
Verification status: ✅ VERIFIED
- Source code: ACCESSIBLE (GitHub)
- Documentation: Included in repository
- Active development: Research code
- Specialized strength: Automated EXAFS fitting with DFT structure database integration