Polycyclic aromatic hydrocarbons, carbon nanoparticles and the diffuse interstellar bands
Bibliographic record
Abstract
Observational data on the appearance and properties of the diffuse interstellar bands (DIBs) are reviewed in the context of a model in which the proposed carriers of these bands are large carbon molecules and carbon nanoparticles containing between 30 and several hundred carbon atoms. The abundance of these carriers, as estimated from the observed strengths of the DIBs, place strong constraints on their rates of formation and destruction, and suggest that the strongest bands, including that at 4428 A, could be produced via the decomposition of larger carbon particles, possibly those particles that have been postulated to be the source of the 2175 A extinction feature. Such particles are of mixed sp2 and sp3 carbon composition, with sizes between that of large molecules and small macroscopic solids. Any description of their characteristics must combine aspects of molecular and condensed matter physics, and this is incorporated in the present discussion. I discuss recent experimental and theoretical data related to these matters.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".