Quantitative matching of crystal structures to experimental powder diffractograms
Why this work is in the frame
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Bibliographic record
Abstract
Identifying whether two experimental crystal structures determined under different experimental conditions correspond to the same polymorph is a challenging problem in crystallography, with practical (and even legal) implications. We recently developed a new quantitative metric for comparison of powder X-ray diffractograms (PXRD), termed the variable-cell powder difference (VC-PWDF) method. VC-PWDF substantially improves the agreement with COMPACK compared to other PXRD-based comparison tools and is recommended to be used in conjunction with COMPACK to improve reliability of structure comparison. We further extended VC-PWDF to allow direct comparison of both experimental and in-silico-generated crystal structures to collected powder diffractograms. The resulting VC-xPWDF method correctly identifies the most similar crystal structure to both moderate and “low” quality experimental powder diffractograms for a set of 7 representative organic compounds, as well as the prolific polymorph former, ROY. This approach should allow for rapid identification of new polymorphs from solid-form screening studies by matching to a set of candidates resulting from crystal structure prediction, without requiring single-crystal analysis.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it