Powder Diffraction Refinement Accuracy via Peak-Shift Criteria
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The Rietveld method for determining crystal structure refinement parameters lacks accuracy due to dependence on sample quality and measurement errors, leading to variations in results among analysts, and conventional indicators are insufficient for obtaining precise lattice parameters.
Innovation Solution
A method and program that calculate and judge refinement parameters using peak-shift criteria, allowing for the selection of true solutions by analyzing multiple sets of converged values and criteria, independent of diffraction angle range or apparatus, thereby improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the conventional Rietveld method is used to determine crystal structure refinement parameters, then the analysis can be performed using familiar diffractometers in short time, but the accuracy of refinement parameters cannot be obtained with high accuracy and results vary among analysts
Solution Approach 1:
The patent segments the refinement parameter determination into two independent parts: (1) conventional Rietveld refinement to obtain preliminary parameters, and (2) a new peak-shift criterion calculation to determine accurate lattice parameters. This segmentation allows each part to serve its specific function without interference, resolving the contradiction between speed and accuracy.
Solution Approach 2:
The patent introduces a new intermediary criterion (peak-shift based criterion) that mediates between the conventional Rietveld method results and the true lattice parameters. This intermediary criterion acts as a bridge that corrects the inaccuracies of conventional methods while maintaining the efficiency of the overall process.
2Reliability
If conventional indicators (Rwp, S) are used to judge goodness-of-fit, then the fitting quality can be assessed, but the lattice parameters cannot be obtained with high accuracy
Solution Approach 1:
The patent moves the accuracy assessment from the conventional intensity-based dimension (y-axis, Rwp, S factors) to a new peak-position-based dimension (x-axis, peak-shift criterion). This dimensional change allows independent assessment of lattice parameter accuracy without compromising goodness-of-fit evaluation.
Solution Approach 2:
The patent extracts the lattice parameter determination from the conventional Rietveld refinement process by introducing a separate peak-shift criterion calculation. This extraction allows lattice parameters to be determined with high accuracy independent of the goodness-of-fit indicators, resolving the contradiction between fit quality assessment and parameter precision.
3Adaptability or versatility
If multiple analysts perform the Rietveld analysis, then different results are obtained due to analyst variability, but the conventional method does not provide a way to identify the true solution
Solution Approach 1:
The patent introduces a feedback mechanism where the peak-shift criterion calculation uses the preliminary refinement parameters as input and provides corrected lattice parameters as output. This feedback loop allows automatic identification of the true solution regardless of which analyst performs the initial refinement, ensuring result consistency.
Solution Approach 2:
The patent makes the system self-correcting by allowing the peak-shift criterion to automatically identify and correct inaccuracies in refinement parameters without requiring expert judgment. This self-service capability eliminates analyst variability and ensures that the true solution is always identified.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Achieves high-accuracy refinement parameters with an accuracy two orders of magnitude better than conventional methods, ensuring results are independent of measurement errors and analyst variability, and applicable for both research and quality control.
Implementation Method 1
By using the X-ray and/or neutron diffraction pattern
Implementation Method 2
By using the X-ray and/or neutron diffraction pattern
Implementation Method 3
The square sum of the weighted residual, SR, is minimized to refine the parameters in the formula during refinements
Data Source
AI summary
The present invention provides a method to calculate refinement parameters from an observed diffraction pattern for powder samples accurately. A method to calculate a best solution of the crystal structural parameters from a diffraction pattern, comprising: a third calculating step of the converged values 600 to calculate at least three converged values; a third judging step of the best converged values 700 to calculate at least three criteria from the peak-shift parameters in the converged values and to judge whether the converged values are a true solution of not by using the criteria; and a first calculating step of a global solution 800 to calculate a global solution of which is the true value by using the criteria.