A Rietveld refinement method for angular- and wavelength-dispersive neutron time-of-flight powder diffraction data

Area of Science:

• Materials Science
• Crystallography
• Neutron Scattering

Background:

• Neutron time-of-flight powder diffraction is a key technique for materials characterization.
• The established Rietveld refinement method requires adaptation for complex diffraction data.
• Existing methods can lead to data reduction steps and loss of high-resolution information.

Purpose of the Study:

• To introduce a two-dimensional extension of the Rietveld refinement method.
• To model neutron time-of-flight powder diffraction data more effectively.
• To improve data analysis by accounting for angular and wavelength variations.

Main Methods:

• Developed a two-dimensional Rietveld refinement approach.
• Incorporated diffraction angle (2θ) and wavelength (λ) variations into the model.
• Validated the method using simulated and real neutron diffraction data.

Main Results:

• Successfully extracted the profile function parameterized in 2θ and λ.
• Achieved excellent refinement residuals for CuNCN using simulated and real data.
• Demonstrated feasible computational efforts for the new method.

Conclusions:

• The novel 2D Rietveld method enhances data analysis for neutron time-of-flight diffractometers.
• The approach avoids data reduction and preserves high-resolution information.
• The method shows potential for integration into existing Rietveld software packages.