A model for mechanochemical transformations: Applications to molecular hardness, instabilities, and shock initiation of reaction
Bibliographic record
Abstract
A basic theoretical structure for mechanochemical transformations based on prior models for solid-state reactions and HOMO–LUMO (highest occupied molecular orbital–lowest unoccupied molecular orbital) gap closing produces the concept of distortion-induced molecular electronic degeneracy (DIMED) of the highest occupied and lowest unoccupied molecular orbitals of an energetic molecule. Both intermolecular and intramolecular charge transfer are involved. The resulting distortion-induced local instability, a mechanochemical effect, leads to chemical transformations and can be analyzed by renormalization of the molecular hardness through the molecular deformation energy. Linear combinations of normal modes are shown to be useful for description of the mechanically induced reaction path. Numerical calculations for the RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) molecule are used to construct a path for initiation of a reaction by shock. They show the breaking of a single N–N bond as the primary step. DIMED is shown to be a kind of “inverse Jahn–Teller effect” leading to the general conclusion that distortion-induced instabilities and mechanically induced reactions require some, but not necessarily complete, HOMO–LUMO gap closure. This indicates that large local strains due to defects or cracks will contribute to DIMED. The DIMED concept, because of its generality, has wide applicability in solid-state chemistry.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".