Precise implications for real-space pair distribution function modeling of effects intrinsic to modern time-of-flight...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Crystallography

Background:

• Total scattering and pair distribution function (PDF) methods are crucial for studying local atomic order and disorder in various materials.
• Modern neutron time-of-flight (TOF) instruments provide high-resolution PDFs over extended length scales.
• Conventional analysis programs often struggle with confounding factors in neutron TOF data, limiting accurate PDF refinement.

Purpose of the Study:

• To explicitly demonstrate the effects of common artifacts in neutron TOF data on real-space PDF analysis.
• To provide a unified presentation of mitigation strategies for these artifacts.
• To offer suggestions for best practices and improved analysis methods for neutron TOF total scattering data.

Main Methods:

• Review of previous literature on PDF analysis artifacts.
• Simulated analysis of neutron TOF data to illustrate artifact effects.
• Case studies using real-world neutron TOF data to demonstrate analysis challenges and solutions.

Main Results:

• Demonstration of how resolution, binning, bounds, peak shape, asymmetry, TOF-to-d spacing conversion, and bank merging impact PDF analysis.
• Identification of confounding factors that are often treated as 'tribal knowledge' within the scientific community.
• Validation of analysis strategies through simulated and real-world data.

Conclusions:

• Accurate PDF analysis requires rigorous accounting for data artifacts in neutron TOF measurements.
• Implementing suggested best practices can significantly improve the reliability of local structure determination.
• Recommendations are provided for enhancing current analysis methods and guiding future neutron instrument design.