Crystal Structure Refinement Using Statistical Restraint Intensity
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Solution Overview
Problem
Existing methods for refining crystal structures using the least squares method can produce chemically unreasonable results due to the lack of an appropriate index for setting restraint intensity, leading to either disregarding measurement data or failing to obtain a chemically reasonable crystal structure.
Innovation Solution
A structure refining apparatus and method that adjusts crystal structure models by applying restraints to ensure a divergence between parameters and known representative values is equivalent to the standard uncertainty, using a σNorm value to determine the contribution of restraint terms and iteratively refine the model until the divergence meets a predetermined range, ensuring statistically feasible restraint intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a strong restraint is applied in structure refinement, then a chemically reasonable crystal structure is obtained, but the measurement data is disregarded
Solution Approach 1:
The patent changes the parameter of restraint intensity from a subjective decision to an objectively determined value based on statistical metrics (σNorm). By calculating the normalized standard uncertainty and setting the restraint contribution accordingly, the system automatically adjusts the restraint strength to balance chemical reasonability with measurement data utilization, resolving the contradiction between these two opposing requirements.
Solution Approach 2:
The patent implements a feedback mechanism where the restraint intensity is continuously adjusted based on the σNorm value calculated from the crystal structure parameters. The system monitors whether the restraint is too strong or too weak and automatically modifies the restraint contribution to achieve optimal balance, preventing both disregard of measurement data and obtaining chemically unreasonable structures.
2Adaptability or versatility
If individual judgment is used to set restraint intensity, then flexibility in analysis is achieved, but univocal and appropriate restraint setting is lost
Solution Approach 1:
The patent enables the structure refinement system to determine the appropriate restraint intensity automatically without relying on individual judgment. The system calculates σNorm from the crystal structure parameters and measurement data, then self-adjusts the restraint contribution accordingly. This self-service mechanism provides both univocality (consistent objective criteria) and adaptability (automatic adjustment to specific cases).
Data Source
AI summary
To provide a structure refining apparatus, a method and a program capable of univocally and appropriately setting a restraint with a statistically feasible intensity and specifying a crystal structure model making use of a measurement result under a constraint condition to reasonable known data. A structure refining apparatus 100 adjusting the crystal structure model on the basis of the measurement result and the known data includes a restraint applying unit 120 configured to apply the restraint such that a divergence between a parameter specifying a crystal structure and a known representative value becomes equivalent to a standard uncertainty of the known representative value and a structure specifying unit 140 configured to specify the crystal structure model on the basis of the measurement result under the applied restraint.